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fe' ’ 







AUTOMOBILE 

IGNITION, STARTING, AND 

LIGHTING 


A Comprehensive Analysis of the Complete Elec¬ 
trical Equipment of the Modern Automobile, 
Including Many Wiring Diagrams and 
Details of All the Important 
Starting-Lighting Systems 



^3^ CHARLES Br HAYWARD 


M 


MEMBER, SOCIETY OF AUTOMOBILE ENGINEERS 
MEMBER, THE AERONAUTICAL SOCIETY 
FORMERLY SECRETARY, SOCIETY OF AUTOMOBILE ENGINEERS 
FORMERLY ENGINEERING EDITOR, “THE AUTOMOBILE” 


ILLUSTRATED 


CHICAGO 


AMERICAN TECHNICAL SOCIETY 

1917 



COPYRIGHT, 1917, BY 

AMERICAN TECHNICAL SOCIETY 


COPYRIGHTED IN GREAT BRITAIN 


AI.L RIGHTS RESERVED 



APR -2 1917 


©CI,A4l)ni38 



INTRODUCTION 


T he fact that less than five years ago self-starters on automobiles 
were practically unknown shows how quickly this device has 
caught the public fancy. Many systems using springs and other 
mechanical devices, compressed air, and electricity were evolved, but 
the ease of coupling electric starting with lighting was too great to 
be ignored, and the electric system alone has survived. Electric 
starting-lighting systems demanded a generator as part of the equip¬ 
ment of every car, and the presence of this source of current had an 
almost immediate influence on the standing of the much favored 
magneto for ignition purposes. Just as a matter of economy, it 
seemed desirable to have the generator charge the storage battery, 
and thus indirectly supply the current for ignition as well as for 
starting and lighting. Many, however, have clung to the reliable 
magneto, and this has resulted in the use by the various makers of 
either the one-unit, two-unit, or three-unit systems, a condition 
which has gained nothing in simplicity by this evolution. 

(L The self-starter developments have also resulted in a large 
increase in the number and difficulty of the electrical problems which 
the repair man in particular is called upon to solve. He has had to 
add many unfamiliar terms to his vocabulary, and has had to find 
out how to trace the wires in the starting circuit, test for grounds or 
for a burned-out armature, and acquire more than a general insight 
into the behavior of the electric circuit under all sorts of conditions. 

Ct. These difficulties have led to an insistent call for a thorough and 
up-to-date treatise on the different starting-lighting systems, which 
demand, the publishers hope, will be abundantly satisfied by this 
handy volume. The author, who for years has been very closely 
associated with automobile and electrical affairs, has tried to present 
his material to meet the needs of the general reader and, at the same 
time, reach the difficulties of the repair man. For the latter classifi¬ 
cation, the wiring diagrams have been carefully analyzed and full 
instructions have been given for the various types. The discussion 
of the earlier as well as the latest models of each particular system 
and the variations of the same system on different cars should be 
particularly helpful. 

CL. The placing on the market of a number of well-designed and inex¬ 
pensive starters for Ford cars has been recognized by the insertion of a 
section entirely devoted to these types. Another new section on the 
care of the storage battery will enable repair men and individual owners 
to properly handle this very essential but much neglected part of the 
electric equipment. 



IGNITION GENERATOR AS DESIGNED FOR REO CARS 

Courtesy of Remy Electric Company, Anderson, Indiana 



REMY STARTING MOTOR AS DESIGNED FOR REO CARS 

Courtesy of Remy Electric Company, Anderson, Indiana 




CONTENTS 

ELEMENTARY ELECTRICAL PRINCIPLES 

PAGE 


The electric circuit. 3 

Current. 3 

Electrical pressun?. 4 

Resistance. 5 

Ohm’s law. 5 

Power unit. 6 

Conductors. 8 

Voltage. 9 

Circuits. 11 

Size of conductors. 16 

Heating effect of current. 18 

Chemical effect of current. 19 

Magnetism. 20 

Natural and artificial magnets. 20 

Laws of magnetic attraction and repulsion. 21 

Electromagnets. 22 

Magnetic field. 23 

Solenoids. 25 

Induction principles in generators and motors. 27 

Induction.‘. 27 

Self-induction. 28 

Capacity of condensers. 29 

Pressure and voltage. ‘. 30 

Friction and resistance. 31 

Current and volume.-. 31 

Power comparison. 32 

Generator principles.. 34 

Elementary dynamo.'. 34 

Commutators. 35 

Armature windings. 38 

Field magnets. 40 

Electric motor principles. 47 

Counter e.m.f. 50 

Types of motors. 50 

Dynamotors. 51 


IGNITION 


Fundamental ignition principles. 

Low-tension system. 

High-tension system. 

Sources of current. 

Primary batteries. 

Storage cells. 

Changes in ignition methods. 

Contact makers, or timers. 

Coils and vibrators. 

Distributor. 

Condenser. 

Hydraulic analogy in ignition system . 

Low-tension magneto. 

High-tension magneto. 

Inductor-type magneto. 


81 

83 

84 
86 
86 

87 

88 

89 

90 

93 

94 
99 

103 

105 

109 




















































CONTENTS 


PAGE 


Sources of current (continued) 

Dixie magneto. . 

Magnetos for eight- and twelve-cylinder motors. 

Ignition systems. 

Dual ignition system. 

Duplex ignition system... 

Double-spark ignition. 

Ford magneto. 

Spark timing. 

Advance and retard. 

Magneto speeds. 

Ignition system fixed timing point. 

Automatically timed systems. 

Firing Order.!. 

Typical firing orders... 

Firing orders and ignition advance for different motors 

Wiring.. 

Magneto mounting.< . . . 

Modern battery ignition systems. 

Effect of starting and lighting developments on ignition 

Westinghouse ignition unit.^.. 

Atwater Kent system. 

Connecticut battery system. 

Remy system. 

Delco system. 

Testing, adjustment, and maintenance. 

Testing. 

Solving troubles.^. 

Ignition instructions. 


112 

115 

118 

118 

123 

124 
124 
129 
129 

137 

138 
138 
143 
143 
147 
162 
167 
170 

170 

171 

172 
175 
178 
181 

192 

193 

194 
201 


ELECTRIC STARTING AND LIGHTING SYSTEMS 


General features.:. 269 

Fundamental characteristics. 269 

Single-wire and two-wire systems. 271 

Constant-current generator. 275 

Inherently controlled generator. 277 

Independent controllers. 279 

Constant-potential generators. 280 

Automatic battery cut-out. 284 

Circuit-breaker. 286 

Requirements in design. 289 

Installation. 293 

Driving connections. 296 

Automatic engagement. 297 

Clutches. 298 

Back-kick releases. 300 

Switches. 301 

Electric horns. 307 

Lighting equipment. 309 

Incandescent lamps. 309 

Lamp voltages. 310 

Reflectors. 311 

Headlight glare. 312 

Dimming devices. 313 

Practical analysis of starting and lighting types. 315 

Buick-Delco type. 318 

Auburn-Delco type. 322 

Chevrolet-Auto-Lite type. 322 

Jeffery-Bijur type. 325 

Circuit-breaker. 325 


/ 



























































CONTENTS 


( 


• 

Practical analysis of starting and lighting types (continued) 

Tracing for grounds. 

Handy test set. 

Auto-Lite system. 

Bijur system. 

Bosch-Rushmore system. 

Delco system. 

Disco system. 

Dyneto system. 

Gray & Davis system. 

Heinze-Springfield system. 

Leece-Neville system. 

North East system. 

Remy system. 

Simms-Huff system. 

Splitdorf system. 

U. S. L. system. 

Wagner system. 

Westinghouse system. 

Installing special systems for Ford cars. 

Genemotor starter. 

Gray & Davis starter. 

Heinze-Springfield starter. 

Fisher starter. 

North East starter. 

Splitdorf starter. 

Westinghouse starter. 

Electric gear-shift. 

General plan. . 

Principle of action. 

Stopping the car. 

Shifting gears. 

Wiring. 

Starting and lighting storage batteries. 

Parts of cell. 

Specific gravity. 

Action of cell on charge and discharge. 

Capacity of battery... 

Construction details. 

Edison cell not available. 

Adding acid.^. 

Hydrometer.*. 

Gassing. 

Sulphating. 

Restoring sulphated battery. 

Specific gravity too high. 

How to take readings. 

Detecting deranged cells. 

Temperature variations in voltage test. 

Cleaning a battery. 

Overhauling battery... 

Lead burning.. 

Installing new battery. 

Charging from outside source... 

Methods of charging.. 

Motor-generator. 

A. C. rectifier. 

Care of battery in winter.... • 

To test rates of charge and discharge.. 

Voltage tests.. 

Cleaning repair parts.... • . 

Summary of instructions on starting and lighting systems 


PAGE 

. 326 
. 328 
. 334 
. 343 
. 360 
. 367 
. 411 
. 411 
. 416 
. 435 
. 443 
. 452 
. 467 
. 479 
. 487 
. 493 
. 507 
. 521 
. 531 
. 531 
. 546 
. 559 
. 574 
. 579 
. 584 
. 594 
. 614 
. 614 
. 614 
. 616 
. 616 
■. 620 
. 623 
. 625 
. 627 
. 627 
. 629 
. 631 
. 632 
. 633 
. 633 
. 641 
. 644 
. 646 
. 647 
. 649 
. 649 
. 650 
. 651 
. 655 
. 661 
. 667 
. 669 
. 672 
. 673 
. 673 
. 675 
. 678 
. 685 
. 689 
. 694 
































































! 










































ELECTRICAL EQUIPMENT FOR 

GASOLINE CARS 

PART I 


INTRODUCTION 

Importance of Electricity on Automobiles. Starting with 
nothing more than a few dry cells and a wiring system that would 
have shamed an itinerant bellhanger, the electrical equipment of 
the automobile has constantly increased in importance, until within 
the last few years it has become the most essential auxiliary there 
is on the machine. Electricity now starts the motor, ignites the 
charge in the cylinders, lights the car and the road ahead, sounds 
the horn, and in some instances shifts the gears and applies the 
brakes. In addition to performing the numerous functions already 
mentioned, it has even gone as far as to displace the flywheel, clutch, 
and gearset altogether, in which case the car is provided with as 
many gradations of speed as a steam car. It seems quite likely that 
along this line is to be one of the most important developments of 
the next few years. 

Inherent Weakness of Electrical Devices. Even in the present 
highly perfected state, the electrical equipment still constitutes the 
weakest element among the motor auxiliaries. In fact, it is subject 
to mmre frequent defection than any other single element of the 
entire construction of the automobile. This must not be taken as 
implying that it is defective in any sense, as it is quite the contrary, 
ignition, lighting, and self-starting systems having been developed 
to a degree of reliability that w^as undreamed of in the earlier days. 
But owing to its nature, the electrical equipment is more susceptible 
to derangement. Consequently, a rather substantial proportion 
of the minor troubles of automobile operation that still survive to 
harass the motorist arise from some failure of the electrical system. 
Of course, many of these are due to the inexperience or ignorance 
of the motorist himself, and for this reason it behooves the student 



2 ELECTRICAL EQUIPMENT 

to give more than the usual amount of attention and study to this 
branch of the subject. 

ELEMENTARY ELECTRICAL PRINCIPLES 

Knowledge of Principles Necessary. To ac*quire a good 
practical working knowledge of electricity as applied to the auto¬ 
mobile today, it is essential not merely to find out how things are 
done, either by watching the other fellow do them, or by studying 
^‘pictures in a book’’, but also to learn why certain things are done 
and why they are carried out in just such a way. Tn other words, 
the man whose knowdedge is based upon theory and principles 
applies knowingly the cause to produce the effect and is certain 
that the desired effect will be produced. On the other hand, the 
man who works only with his hands aimlessly goes from one thing 
to another trusting chiefly to luck to accomplish tw'o things. One 
of these is to strike upon the remedy for the trouble the cause of 
which is sought, and the other is to deceive the spectator usually 
the ownier of the car—into believing that the fumbler really knows 
what he is about. 

There are accordingly tw^o distinct classes of knowdedge as 
regards the electrical equipment of an automobile—one which is 
picked up by rote, an isolated point at a time, and applied in the 
same manner, and the other which is based upon a clear insight 
into the underlying reasons for the various actions and reactions 
that make up the different electrical phenomena involved. If 
we want to know^ wdiat is wrong wdth an electric motor, it is essential 
that W’e should know wdiat makes an electric motor operate when 
everything is right. In the same w^ay, it w^ould be groping in the 
dark to attempt to investigate the reasons for the failure of a dynamo 
to generate current, or a storage battery to give up its charge, 
if W’e had no knowledge of why a dynamo, wdien run by an outside 
source of energy, normally produces a current, or w^hy an accumu¬ 
lator literally ^‘gives back” wdiat has been put into it wdien its 
circuit is closed after charging. 

It will accordingly be the function of this introductory chapter 
to give a brief resume of the principles underlying the operation 
of w hat has come to be the most important auxiliary of the gasoline 
motor as applied to the automobile—its electrical equipment. 


ELKCTKIC^AL EQUIPMENT 


3 


A thorough understanding of these principles will go a long way 
toward enabling one to remedy the various minor ills that afflict 
the apparatus, and to recognize at once those of a nature serious 
enough to be beyond the first aid which even the best equipped 
garage is capable of giving. It is worse than a waste of time to 
hunt for a short circuit or a ground as the cause of failure of the 
dynamo to generate, when an inspection of its parts reveals the 
fact that its armature winding has been burned out. Again, one 
can hardly expect the motor to continue starting the gasoline engine 
when the owner’s neglect of the storage battery has permitted the 
l)lates to sidphate so badly that they are ])ractically worthless. 
C ontempt of “book knowledge” is not wholly a thing of the past, 
and many men consider themselves “practical” in insisting upon 
learning how to do things with their hands alone. The best-paid 
man, however, and he who can instruct others how things should 
be done, is the man who uses his head to acquire a knowdedge of 
the theory upon which practice is based, and then employs his 
hands to much better effect by letting his brain guide them. 

THE ELECTRIC CIRCUIT 

Current. Just what electricity is we do not know—maybe 
we never shall know—but it is a matter of common knowledge that 
it is one of nature’s prime forces and as such is universal. The 
air, the earth, the water, the clouds, our bodies and those of animals, 
as well as inanimate objects such as trees, houses, and the like 
are all electrified to a greater or less degree all the time. The 
amount of electricity that any given object possesses at a given 
moment depends upon its capacity (the electrical meaning of which 
is given later) and the conditions of surrounding objects. For 
example, a room will hold a certain amount of air; if it is unin¬ 
fluenced by other conditions, we know that the room is full of air 
at an approximate atmospheric pressure of 15 pounds to the square 
inch (the usual pressure at sea level). The room may be considered 
in a normal “state of charge”. 

There is nothing that differentiates the air in this room from 
that of the room adjoining. It is perfectly quiet and nothing is 
disturbing it; there is no tendency for it to move. If, however, 
all the openings of the room are tightly closed with the exception 


4 


ELECTRICAL EQUIPMENT 

of a duct for the admission of more air under the impulse of a power¬ 
ful compressor, in a very short time there will be a marked difference 
between the air in this room and the air in the other rooms. Instead 
of the normal atmospheric pressure of 15'pounds j)er square inch, 
there will be a pressure against all parts of the room—floor, walls, 
and ceiling—of 50, 60, or 100 pounds, according to the length of 
time the compressor has been working and the degree of tightness 
with Avhich the various openings have been closed. Thus there 
will be a great deal more air in the one room than, in its neighbors. 
If it were electricity instead of air, the room would be said to be 
highly charged. 

The air in this room, on account of the pressure which it is 
under, is constantly seeking an outlet, and it vill gradually leak 
out through various small openings, probably without its escape 
being noticed. The same conditions obtain when a body becomes 
electrified beyond its capacity to hold a charge—the charge of 
electricity Avill leak away without giving any indication of its passing. 
Turning again to the room containing the compressed air, if a door 
or window of that room is opened suddenly, the pressure is immedi¬ 
ately released through that opening and anyone standing in front 
of it would say that a strong current of air blew out. In the case 
of electricity, if any easy path of escape is provided, the entire 
charge will rush away from the body, and there is then said to be 
a current of electricity 'Towing” from this point of escape to what¬ 
ever other object equalizes the pressure by becoming charged. 
An electric current is accordingly electricity in motion; it is simply 
said to flow. But to cause it to do so there must be pressure. The 
electrical term for this pressure is potential or voltage. 

Electrical Pressure. Every day in the year the earth transmits 
a greater or less proportion of its electrical charge to the atmos¬ 
phere, or receives a charge from the latter, but unless the conditions 
are favorable there is no visible indication of this difference of 
potential as it is termed. It must be borne in mind that this differ¬ 
ence of potential, or difference in electrical pressure, between two 
points is what causes a current to flow. Given a hot day in summer, 
however, when the air is heavily charged with moisture and low 
cumuli, or rain-charged clouds form in great masses, then the 
electrical charges from the earth and the air accumulate in these 



ELECTRICAL EQTTIPIMENT 


5 


great banks of dense water vapor instead of passing np to the higlier 
regions of the atmosphere. When the charge exceeds the capacity 
of the clouds, and the electrical pressure, or difference of potential, 
between two neighboring clouds or between a cloud and the earth 
becomes very great, we have the familiar phenomenon of lightning, 
the electricity escaping in a several-mile-long flash instead of by 
means of the little spark with its snap as it passes from one object 
to another under similar conditions. 

Resistance. It is thus apparent that electricity is an element 
that can be expressed as a quantity, and likewise one that can be 
subjected to pressure. The unit of current is the ampere; the unit 
of electrical pressure is the volt; the unit of quantity is the coulomb^ 
equal to one ampere per second. Resuming the simile previously 
given, 500 cubic feet of air forced into the room under a pressure 
of 100 pounds to the square inch, may be likened to a current of 
500 amperes at 100 volts. And, just as the opening allowed 
determines the quantity of air that will escape at a time, so the 
electrical outlet influences in the same manner the current that 
will flow. From this it is evident that there is another factor to 
be considered. This is resistance. 

If a half-inch hole is bored in the door of the room, the air 
will escape at a pressure of 100 pounds to the square inch, but 
only a few cubic feet per minute can pass through the orifice. If 
a very fine wire is used to tap the given charge of 500 amperes 
at 100 volts, the current will have a potential of 100 volts, but very 
few amperes will pass through the fine wire. If the pressure back 
of the air is increased, however, more air will be forced through 
the small opening in the same time; and if there is a greater potential 
})ack of the electrical current, more current will be passed through 
the fine wire. Thus the factors of electrical quantity, pressure, 
and flow are all related and are all dependent on the factor of 
resistance. The unit of resistance is the ohm. 

Ohm’s Law. From this interrelation has been deduced what 


is known as Ohm’s law, usually expressed as I = 


E 


or current equals 


voltage divided by resistance, E denoting the electromotive force, 
which is only another term for voltage or potential—the electrical 
moving force back of the current 7, 


f) 


ii:T.EC"riurAL equipment 


As a practical application of the preceding foriiiula, take the 
case of a small conductor connecting the battery and starting 
motor of the electrical starting system on an^ automobile. The 
diameter of the wire is such that the length required to connect 
the two points has a resistance of 10 ohms. One ampere is that 
amount of current which will pass through a conductor having 
a resistance of one ohm under a pressure of one volt. The starting 
system in question operates at 6 volts. Hence, /=iV = .6, that 
is, the battery would be able to force only .6 ampere through that 
small wire, and the starting motor w^ould not operate. 

It is apparent from the foregoing that the formula for Ohm’s 
law may be transposed to find any one of the three factors that 
may be unknown. For example, given the conditions just men¬ 
tioned, w^e may determine how much resistance the wire in question 
has. The resistance equals the voltage divided by the current: 


that is, R = —r, or resistance equals -— = 10 ohms. Or again, if it is 
I .b 

desired to learn what voltage is necessary to send a current of .6 
ampere through a resistance of 10 ohms, the solution calls for an 
equally simple transposition of the formula. Given any tw’o factors, 
then the third may be readily determined. 

Ohm’s law is absolutely fundamental in all things pertaining 
to electrical operation, and the man who wants to make his knowledge 
of the greatest practical use will do well to familiarize himself with 
it. Naturally it does not enter into repair work to more than a 
small fraction of the extent that it enters into the design of motors, 
generators, and other electrical devices, but a knowledge of it is 
of distinct value. 

Power Unit. To go back to the simile of air under pressure, 
it is apparent that the energy released by the lowering of this 
pressure may be made to perform useful work, such as driving a 
compressed-air drill, running a small air motor, or the like. So 
with the electric circuit, the drop from a higher to a lower potential, 
which causes a current to flow, is a source of power. Electrical 
power is the product of the amperage or current multiplied by the 
voltage at which it is applied. The power unit is the ivatt and it 
is equivalent to one ampere of current flowing under a pressure, 
or potential, of one volt. There are 746 watts in a horsepower. 



ELECTRICAL EQUIPMENT 




Electrical computations, however, are based on the metric system 
to a large extent, so that instead of being figured in horsepower, 
electrical energy is figured by the kilowatt, or a unit containing 
one thousand watts, and the charge therefor is based upon the length 
of time for which this amount of energy is employed. From this 
comes the now familiar expression '‘kilowatt-hour”. 

The power equivalent is expressed as P = IXE, current multi¬ 
plied by electromotive force (potential), and, as in the case of Ohm’s 
law, with any two of the factors given, the third may be readily 
determined. For example: How much power is developed by 
a 6-volt starting motor if 125 amperes of current are necessary 
to turn the automobile engine over fast enough to start it? The 
amount of current given is an arbitrary average taken simply for 
the purpose of illustration, for in overcoming the inertia of an 
automobile engine a great deal of current is required at first, the 
drain on the battery often exceeding 250 amperes for a few seconds, 
then dropping as the engine turns over to about 50 or GO amperes. 
Taking 125 as the average, we have 125X6 = 750 watts = .75 kilo¬ 
watt, or slightly over one horsepower. 

Granting that one horsepower is necessary to turn over a 
by 4-inch six-cylinder motor at 75 r.p.m.—a speed that has been 
predetermined as necessary to cause it to take up its own cycle 
under the most adverse starting conditions—and given a 6-cell 
storage battery capable of developing a potential of 12 volts, then 

T“i0 

we have: I — or current = -— =62.1 -f amperes, which represent 

Itj -I ^ 


the average demand upon the storage battery to start that engine 
under normal conditions. This illustration and the previous one 
show the working of Ohm’s law; doubling the voltage halves the 
amount of current necessary. As the life of a storage battery is 
largely determined by the rapidity as well as by the number of 
its discharges, and as the storage battery is the weakest element 
in any electric lighting-and-starting system, it may well be asked 
why the 12-volt standard is not universally adopted, or why, as 
is done in some cases, a 24-volt battery is not employed and the 
current consumption again reduced by half. Just why this is not 
done is explained in detail in the section on the voltages employed 
in electric starters generally. 



ELECTRICAL EQUIPMENT 


S 


Conductors. To lead steam or air under pressure from a 
boiler or compressed-air reservoir to the point at which it is to be 
utilized as energy, it is desirable to use a conductor that will not 
waste too much of this energy in useless friction. That is, the 
conductor must be of ample size in proportion to the volume to 
be conveyed, smooth in bore, and free from sharp turns or bends. 
The transmission of electrical energy involves some of the same 
factors. While neither the smoothness of the bore nor the presence 
of bends and turns has any effect, they have their counterpart 
in the conductivity of the material of which the wire is made, the 
size of the wire in proportion to the amount of current to be carried 
being also a matter of prime importance. 

Resistance of Materials. Materials differ greatly in their 
ability to conduct an electric current, or, to put it the other way 
around, they differ in the amount of resistance that they offer to 
the passage of the current. Silver in its pure state heads the list 
in the table of relative conductivities, and it is accordingly said 
to possess a relative resistance of one, or unity; the resistance of 
every other material may be expressed by a number which repre¬ 
sents the resistance of that particular substance as compared with 
pure silver. Naturally silver does not represent a great possibility 
for commercial use, and so copper, which is second on the list, is 
almost universally employed. Pure copper is very soft and is 
lacking in tensile strength; it is therefore alloyed, and it is also 
hardened in the drawing process; both of these processes increase 
its resistance slightly over the factor usually accorded it in the 
standard table of specific conductivities of materials. In this 
table, German silver (which is an alloy containing no silver whatever 
and having but a few of its properties), cast iron, steel, carbon, 
and similar substances will be found well down toward the end. 
They are known as ^Tigh-resistance’’ conductors and are usually 
used where a certain amount of resistance to the current is desirable. 

It must be borne in mind that ability to conduct a given amount 
of current without undue loss through resistance depends upon 
the size and the length of the conductor quite as much as upon 
the material. In other words, if a steel rail is only one-thirtieth 
as good a conductor as a copper cable, it will require a cross-section 
of steel thirty times as great as that of a copper cable in order to 


j 


ET.ECTRICAL EQUIPMENT 


0 


conduct the current with the same ease—that is, to make a con¬ 
ductor of equal resistance. An illustration of this may be seen 
in the overhead copper wire of the usual trolley system. This 
wire of about one-half inch diameter forms one of the conductors, 
while the two steel rails form the ^Teturn”. A similar example 
may be found in what is known as the single-wire system of installa¬ 
tion for an electric starter in automobiles. A single copper cable 
conducts the current from the battery to the starting motor, while 
the steel frame of the automobile is the return side of the circuit, 
or vice versa. 

Voltage Drop. It is evident that the resistance of a circuit 
varies inversely as the size of the conductor—the larger the cross- 
section of a conductor, the less its resistance—and increases directlv 
as its length, besides depending upon the specific resistance of the 
material. The specific resistance of the metals constituting elec¬ 
trical circuits on the automobile are (silver being 1.0); copper 
1.13, varying more or less with its hardness; aluminum 2.0; soft 
iron 7.40; and hard steel 21.0. Thus, 9.35 feet of No. 30 copper 
wire are required for a resistance of one ohm, while only 5.9 inches 
of hard steel wire of the same gage are required to present the same 
amount of resistance to the current. If the length of the conductor 
is doubled, its resistance is doubled, which accounts for the placing 
of the storage battery as close as possible to the starting motor. 
Eurthermore, the heavy starting currents which are required by 
the motor demand the use of heavy copper cable for this circuit. 
If two wires are of the same length but one has a cross-section 
three times that of the other, the resistance of the former is but 
one-third that of the latter. If a circuit is made up of several 
different materials of diff'erent sizes joined in series with one 
another, the total resistance will be the sum of the resistance of 
the various parts. 

In addition to being affected by the cross-section and the length, 
the resistance is also influenced by the temperature. All metals 
increase in resistance with an increase in temperature, that of copper 
increasing approximately .22 per cent per degree Fahrenheit. The 
change of resistance of one ohm per degree change in temperature 
for a substance is termed its temperature coefficient. Metals have 
a positive temperature coefficient; some materials, like carbon. 


10 


ELECTRICAL EQUIPMENT 


have a negative temperature eoelHeieiit, that is, they decrease 
in resistance with an increase in temperature. 

It is consequently necessary to employ wires of proper size 
to carry the amount of current required by the apparatus in circuit 
—such as lamps—without undue heating, which would cut down 
the amount of current flowing. For the same reason it is also 
desirable to make the circuits as short as practicable, since in addition 
to cutting down the current, the resistance also cuts down the 
effective voltage. That is, there is a fall of potential, or drop in 
voltage, between the source of current supply and the apparatus 

j 

utilizing it, due to the resistance of the conductors between them. 
This voltage drop is further increased by joints in the wiring and 
by switches. It is apparent that the lower the voltage of the source 
of supply, the more important it becomes to minimize the loss, 
or voltage drop, in the various circuits. For this reason lighting 
or other circuits on the automobile should never be lengthened 
where avoidable. When necessary to extend a circuit for any 
reason, wire of the same diameter and character of insulation as 
that forming the original circuit must be employed, and the joints 
should be as few as possible, all mechanically tight, and well soldered. 
The voltages employed in the electrical systems of automobiles 
are so low—varying from 6 to 24 volts, with a strong tendency 
to standardize the 6-volt system—that any increased resistance 
is likely to cause unsatisfactory operation. 

Non=Conductors. In going down through a table of specific 
conductivities of various materials, the vanishing point is reached 
with those that cease to be conductors at all. Such materials 
are known as nonconductors or insulators, and some substances 
vary in the degree of insulation they afford quite as much as other 
materials do in their ability to conduct a current. Glass, rubber, 
shellac, oil, paraffin wax, wood, and fabrics are all good insulators 
when perfectly dry. Distilled water has such a high resistance 
as to be almost an insulator, but in its natural state water contains 
alkaline salts or other impurities that make it a conductor. Con¬ 
sequently, when any otherwise good insulating substance is wet, 
the current is likely to leak across the wet surface of the insulator. 
This is particularly the case with a current of high potential, or 
high tension, and explains why it is of the greatest importance 


ELECTRICAL EQUIPMENT 


11 

to keep all parts of the secondary side of the ignition system perfectly 
dry. The ])otential which causes the current to arc across the gap 
of the spark plug is so high that it will leak across even slightly 
damp surfaces, such as the porcelains of the plugs. This leakage 
is often visible, especially in the dark, and it may also be detected 
by placing the bare hand on the porcelain. 

Just as the amount of current to be carried determines the 
size of the conductor to be employed, so the potential or pressure 
under which this current is transmitted determines the amount of 
insulation that will be necessarv. The latter is also affected, how- 
ever, by mechanical reasons, for example, by the liability of the 
conductor to chafing or abrasion. The best grades of copper 
cable employed for both ignition and starting-lighting systems on 
automobiles today are stranded, that is, composed of a number 
of fine wires, to make them flexible. The stranded cable is then 
tinned to prevent corrosion due to the sulphur in the insulation, 
after which it is covered with a soft-rubber compound of a thickness 
dependent upon the purpose for which the wire is intended. For high- 
tension ignition wiring this rubber covering will be fully one-half inch 
thick. This covering is vulcanized and is then further protected by 
braided linen, or silk-cotton thread which is made waterproof by 
being impregnated with shellac or some other insulating compound. 

Circuits. When air under high pressure escapes from its 
container, it simply mingles with the atmosphere, and as soon as 
the difference in pressure is equalized there is no distinction between 
it and air in general. But to equalize a difference in potential 
of an electric current there must be a conducting path between 
the points of high and low potential. This is termed a circuit. 
Current to operate trolley cars is fed to the motors of the car from 
the overhead wire and returns through the tracks to the generators 
at the power house. This is known as a gromid-return circuit. 
In the single-wire electric starting system of an automobile, current 
from the storage battery reaches the starting motor through the 
starting switch and a single heavy cable, and returns through the 
frame and other metal parts of the car itself, or vice versa. This 
is another instance of a ground-return circuit. 

Both the primary and secondary sides of the ignition system 
of an automobile are also grounded circuits. In contrast with 


12 ELECTRICAL EQUIPMENT 

this, the circuit may be coinposecl of copper cables directly con¬ 
necting both poles of the battery and switch with the startmg 
motor. The highly insulated cable employed for both ignition 
and starting systems is expensive and the use of a single wire greatly 
simplifies the connections, considerations which account for the 
general use of this type of circuit. A circuit is said to be open when 
there is a break in it which prevents the current from flowing, as 



when the svutch is opened, or when a connection or the wire itself 
is broken. 

Series Circuit. The connections between a storage battery, 
switch, and starting motor, comprise the simplest form of circuit, 
in which the motor is said to be in series with the batterv, and 
the cells of the battery are in series with one another. This is 
termed a series circuit and a break in it at any p.oint opens the 
entire circuit. The starting motor. Fig. 1 (a), requires the entire 
output of the storage battery for its operation. ' 

































ELPJCTRICAL EQUIPMENT 


13 


To make clear the distinction between this and other forms 
of circuit, it must be borne in mind that, in equalizing a potential 
difference, electric current flows from the positive or plus side 
of the source of supply, whether a battery or generator, to the negative 
or minus side (plus and minus being arbitrary signs employed to 
distinguish the positive and negative sides of a circuit or of an 
instrument). The current is said to flow out on the positive side 
of the circuit and to return on the negative side. In the case of a 
series circuit as described, the current flows through each piece 
of apparatus in turn; each receives all the current in the circuit 
at a potential proportioned to the resistance of the apparatus in 
question. For example, in the simple starter circuit referred to 
above the starting motor receives the entire output of the 3-cell 
storage battery at its full voltage of G volts, less the drop in voltage 
due to the resistance of the circuit. If there were two starting 
motors instead of one in the circuit, both in series, both would 
receive all the current but at only half the voltage. 

Multiple or Shunt Circuit. As opposed to this, in a multiple 
circuit. Fig. 1 (b), in which every piece of apparatus is connected to 
both sides of the circuit “in parallel”, each piece of apparatus in 
the circuit receives current at the same voltage but draws from 
the circuit the current determined by its resistance. The failure or 
withdrawal of any one or more instruments in a multiple or parallel 
circuit has no effect on those remaining. The lighting circuits 
of an automobile equipped with a 6-volt starting system are an 
example of this. Each lamp is designed to burn to its maximum 
illumination at 6 volts, but the 25-candle-power headlights take 
more current than the 5-candle-power side lights or the 2-candle- 
power taillight, owing to the difference in the size and resistance of 
their filaments. Removing any one of the bulbs has no effect on 
any of the others, because all are in parallel. 

Series-Multiple Circuit. A combination of the two forms of 
circuits is sometimes necessary to accommodate different devices 
designed for varying voltages. For example, it is usually found 
expedient to burn 6-volt lamps on the 12-volt starting systems. 
In such a case, the starting motor is in series with the battery and 
receives the full voltage as well as the full current. The lamps are 
divided into two groups, each group comprising a parallel or mul- 


14 


ELECTRK^AL EC^nPMENT 


tiple circuit of its own, and these two groups are connected in .series 
so that the lamps in each circuit receive 6 volts, but the circuit 
as a whole takes the battery current at 12 volts. Such a combination 



is known as a series-parallel or series-multiple circuit and is more 
or less commonly used for connecting dry cells for ignition use, 
Eig. 2. 

Circuits may also be interdependent, that is, practically a 
circuit on a circuit. The method of connecting up the voltmeter 
that is mounted on the dash of the car is an instance of this, a wire 
being led from each side of the main circuit to the instrument. 
The instrument is then said to be in shunt, Eig. 3, and the amount 
of current that is diverted to it is entirely dependent on the 
resistance. As a voltmeter is wound to a high resistance, Eig. 4, 
it is designed to take very little current for its operation. The 



Fig. 3. Diagram Showing How Voltmeter Is 
Shunted in the Circuit 


ammeter, big. 5, on the other hand, is intended to indicate the entire 
current outj)ut of the generator on charge or discharge, and is 
accordingly connected in series so that all the current passes through 




































ELECTRICAL EQUIPMENT 


15 




it. (Owing to the heavy rush of current taken by a starting motor 
in overcoming the inertia of the gasoline engine, the ammeter is 
not included in this circuit.) 

Short = Circuits and 
Grounds. The previous par¬ 
agraphs have made clear the 
necessity for having a com¬ 
plete path or circuit for the 
current in order that its power 
may be utilized. There must 
be a connecting cable on one 
side and there must be a re¬ 
turn on the other (grounded 
circuit). If instead of pass¬ 
ing through' the apparatus, 
such as the starting motor, 
the current finds an easier 

path through an abrasion in Fig. 4. Diagram of Voltmeter Principle 

the insulation of the cable 
and some metal part against 
which that touches, it is 
said to be short-circuited. A 
case such as that cited, 
where a stripped cable 
touches a metal part, so 
that the current completes 
the circuit without passing 
through the motor, is 
usually termed a ground. 

This should not be confused 
with the ground return pre¬ 
viously mentioned as a 
characteristic of the wiring 
of many of the starting and 
lighting systems in use on 

automobiles today. It is indeed a ground return but not an 
intentional one. It is also true that a ground of this type is 
a short circuit, but it does not necessarily follow from this that 


Fig. 5. Diagram of Ammeter Principle 






































16 


ELECTRICAL EQUIPMENT 


all short circuits are grounds, as short circuits may occur from 
many other causes—for instance, where two wires touch at unin¬ 
sulated points or where stray metal makes contact with connec- - 
tions, etc. 

Size of Conductors. The influence of the factor of resistance 
makes plain the reason for using wires of different sizes for the various 
circuits of the ignition starting and lighting systems of the auto¬ 
mobile. If an ample flow of compressed air is desired for power 
purposes, a liberal outlet must be provided, while if only a small 
spray is required, as for cleaning purposes, a small-bore tube will 
suffice. If we try to employ the small-tube line for power pur¬ 
poses, we shall not gain the desired result because its resistance is 
so great that it will not permit a sufficient flow of air. For the 
same reason a conductor of much larger diameter and, therefore, of 
correspondingly low resistance must be employed to handle the 
heavy current necessary to operate the electric starting motor, than 
is needed for the comparatively small current which is demanded by 
the ignition system. 

Whether it is mechanical or electrical in its nature, the power 
necessary to overcome resistance is liberated in the form of heat. 
Mechanical resistance is friction and its presence between moving 
bodies always generates heat. Electrical resistance may, for the 
purpose of illustration, be termed internal or molecular friction, 
and it also results in heat. The extent of the rise in temperature 
of a conductor or wire, depends entirely upon the proportion that 
its size and, consequently, its current-carrying ability bear to the 
amount of current that is sent through it. Roughly speaking, if 
a wire is three-fourths the size it should be to carry the starting 
current, it will become uncomfortably warm to the hand after the 
motor has been operated several times in succession. If it is only 
one-half the size it should be, continuous operation of the starting 
motor for a few minutes will doubtless burn off most of the insulation. 
Further reducing its size would cause the wire to become so hot 
as to set fire to the insulation the moment the current was turned 
on, and any great decrease in diameter would result in the immediate 
fusing of the wire itself. The wire would literally ‘‘burn up” and 
in a flash. 

It would not be practical to attempt to conduct live steam 


ELECTRICAL EQUIPMENT 


17 


TABLE I 


American Wire Gage (B. & S.) 


No . 

Diameter in 

Circular 

Mils 

Ohms 

per 

1000 

Ft. 

No. 

Diameter in 

Circular 

Mils 

Ohms 

per 

1000 

Ft. 

Mils 

Mm. 

Mils 

Mm. 

0000 

460.00 

11.684 

211600.0 

.051 

19 

35.89 

.912 

1288.0 

8.617 

000 

409.64 

10.405 

167805.0 

.064 

20 

31.96 

.812 

1021.5 

10.566 

00 

364.80 

9.266 

133079.4 

.081 

21 

28.46 

.723 

810.1 

13.323 

0 

324.95 

8.254 

105592.5 

.102 

22 

25.35 

.644 

642.7 

16.799 

1 

289.30 

7.348 

83694.2 

.129 

23 

22.57 

.573 

509.5 

21.185 

2 

257.63 

6.544 

66373.0 

.163 

24 

20.10 

.511 

404.0 

26.713 

3 

229.42 

5.827 

52634.0 

.205 

25 

17.90 

.455 

320.4 

33.684 

4 

204.31 

5.189 

41742.0 

.259 

26 

15.94 

.405 

254.0 

42.477 

5 

181.94 

4.621 

33102.0 

.326 

27 

14.19 

.361 

201.5 

53.563 

6 

162.02 

4.115 

26250.5 

.411 

28 

12.64 

.321 

159.8 

67.542 

7 

144.28 

3.665 

20816.0 

.519 

29 

11.26 

.286 

126.7 

85.170 

8 

128.49 

3.264 

16509.0 

.654 

30 

10.03 

.255 

100.5 

107.391 

0 

114.43 

2.907 

13094.0 

.824 

31 

8.93 

.277 

79.7 

135.402 

10 

101.89 

2.588 

10381.0 

1.040 

32 

7.95 

.202 

63.2 

170.765 

11 

90.74 

2.305 

8234.0 

1.311 

33 

7.08 

.108 

50.1 

215.312 

12 

80.81 

2.053 

6529.9 

1.653 

34 

6.30 

.160 

39.7 

271.583 

13 

71.96 

1.828 

5178.4 

2.084 

35 

5.61 

.143 

31.5 

342.433 

14 

64.08 

1.628 

4106.8 

2.628 

36 

5.00 

.127 

25.0 

431.712 

15 

57.07 

1.450 

3256 7 

3.314 

37 

4.45 

.113 

19.8 

544.287 

16 

50.82 

1.291 

2582.9 

4.179 

38 

3.96 

.101 

15.7 

686.511 

17 

45.26 

1.150 

2048.2 

5.269 

39 

3.53 

.090 

12.5 

865.046 

18 

40.30 

1.024 

1624.1 

6.645 

40 

3.14 

.080 

9.9 

1091.865 


at high pressure through a cardboard tube. Nor is it any more 
so to attempt to send a heavy current through “any old piece of 
vvire’\ Electric lighting and starting systems as they exist on cars 
today are of all degrees of merit. The cars themselves have reached 
a stage of reliability where their useful life is now on the average 
from five to ten years or more. Consequently, there are a great 
many cars in service equipped with electric systems that were 
brought out several years ago. These are the cars on which the 
repair man will get a.great deal of his early experience, and he 
need not take it for granted that just because the electric systems 
have worked for a certain length of time they were properly designed 
at the outset. Overheated conductors not only indicate excessive 
resistance caused by small wires or poor joints, but they also indicate 
a waste of power that is being drawn from the battery and dissi¬ 
pated in the air. The utilization of this energy or rather the 
prevention of its transformation into heat would mean all the 
difference between poor and good operation between an efficient 
and a wasteful system. 






















18 


ELECTRICAL EQUIPMENT 


Heating Effect of Current. The amount of heat that a given 
current will produce in passing through a conductor of a certain 
size is expressed by Joule’s law: The number of heat units developed 
in a conductor is proportionate to its resistance, to the square of the 
current, and to the time that the current lasts. 

The heat generated, therefore, increases in direct proportion to 
the resistance. For example, if the cable between the starting 
motor and the battery be replaced by one-half its size, the resistance 
will be doubled and the heat generated will increase in the same pro¬ 
portion, the current remaining the same in both instances. Increasing 
the current, however, adds to the amount of heat generated, as the 
square of the increase. Thus, if with the original starting cable above 
mentioned, the amount of current necessary to start the motor has 
to be doubled, owing to gummed lubricating oil or stiff bearings, the 
volume of heat generated will increase fourfold. The amount of 
heat generated also increases in direct proportion to the time that 
the current lasts. It will be easy to realize from this why abnormal 
conditions may quickly bring the heating effect of the current to a 
point where the insulation of the wires, or even the wires themselves, 
may be endangered. For instance, in the case of a motor that is 
very hard to start, the discharge from the battery is greatly increased 
in turning it over, and the starting motor must be operated for a very 
much longer period to get the engine under way, causing a direct 
increase in the heating effect, due to the longer time that the current 
is passing through the cable, and a fourfold increase for the addi¬ 
tional current necessarv. 

Heat Generated in Starting Motor. Take the case of a motor 
that requires 150 amperes for the first few seconds and 50 amperes 
once the engine is turning over freely. If stiff* bearings or gummed 
oil cause the initial current to rise to 200 amperes and the running 
current to 80 amperes for a period three times as long as would ordi¬ 
narily be required to start, there will be a very considerable increase 
in the number of heat units generated. This is one of the reasons why 
it is good practice to use the starting motor intermittently when the 
engine does not at once fire and take up its own cycle, instead of 
running the starting motor continuously until the engine begins to 
fire and generate its own power. A much more important reason, 
however, is the fact that the intermittent use of the starting motor 


ELECTRICAL EQUIPMENT 


19 


is not nearly so hard on the battery, as the storage battery recu¬ 
perates very quickly when given short periods of rest between the 
demands for its power. Running the starting motor for ten periods 
of 30 seconds each, with a like interval between the attempts to start, 
will not discharge the battery anything like as much as will operating 


the starting motor continuously for five minutes. A longer rest 
between trials will be of greater benefit to the battery. 

Heating Effect on Lamps and Fuses. It must not be concluded 
from the above that the heating effect of the current is always detri¬ 
mental, as it is taken advantage of in many ways. Two of the com¬ 
monest of these are the incandescent lamp and the fuse. In the case 
of the former, the increase in heat with an increase in resistance is 
mainly depended upon, the filament being made of such a size that 
a given amount of current at a certain voltage will just bring it to 
incandescence. For this reason an increase in the current, or voltage, 
will burn the filament and destroy the lamp. The fact that the 
heating effect increases as the square of the current is taken advantage 
of in the design of fuses which are made of soft alloys that will melt 
at comparatively low temperatures. Resistance is also a factor in the 
fuse, as in cutting down the cross-section of the fusible wire the resist¬ 
ance is increased, while the current-carrying capacity of the wire is 
decreased. The cross-section, or diameter, of the fuse is gaged to 
carry the amount of current that is a safe load for the circuit and 
the apparatus in it plus a reasonable factor of safety to prevent 
the fuse from burning out, with a small percentage of increase that 
would do no damage. For example, a 10-ampere fuse, such as is 
used in connection with many automobile-lighting generators, would 
seldom burn out with an increase in the current to 12 amperes or 
even to 15 amperes for short periods, as the time element is also 
important. Some other applications of the heating effect are electric 
welding, blasting fuses, soldering coppers, cooking utensils, and the like. 

Chemical Effect of Current. The passage of an electric current 
likewise has a chemical effect depending upon the nature of the con¬ 
ductor. This may take various forms, such as the conversion of one 
chemical compound into another, as in the case of the storage battery; 
the decomposition of water into hydrogen and oxygen; the deposition 
of metals, as in electroplating; or the decomposition of metals, as 
in electrolysis. 


20 ELECTRICAL EQUIPMENT 

TABLE II 


Carrying Capacity of Wires 


B. & S. Gage 

Circular Mils 

Rubber 

Insulation 

Other 

Insulation 

Amperes 

Amperes 

18 

1,624 

3 

5 

16 

2,588 

6 

- 8 

14 

4,107 

12 

16 

12 

6,530 

17 

23 

10 

10,380 

24 

32 

8 

16,510 

33 

46 

6 

26,250 

46 

65 

5 

33,100 

54 

77 

4 

41,740 

65 

92 

8 

52,630 

76 

110 

o 

66,370 

90 

131 

1 

83,690 

107 

156 

0 

105,500 

127 

185 

00 

133,100 

150 

220 

000 

167,800 

177 

262 

0000 . 

211,600 

210 

312 

V 


MAGNETISM 



Natural and Artificial Magnets. It has been known for many 
centuries that some specimens of the ore known as magnetite (Fe 304 ) 

have the property of attracting small bits 
of iron and steel, Fig. 6. This ore proba¬ 
bly received its name from the fact that it 
is abundant in the province of IMagnesia 
in Thessaly, although the Latin writer 
Pliny says that the word magnet is de¬ 
rived from the name of the Greek shep¬ 
herd Magnes, who, on the top of Mount 
Ida, observed the attraction of a large 
stone for his iron crook. Pieces of ore 
which exhibit this attractive property 
for iron or steel are known as natural 
magnets. 

It was also known to the ancients 
that artificial magnets could be made by 
, stroking pieces of steel with natural mag- 

Lodestone iiets, but it was iiot Until the twelfth 



















ELECTRICAL EQUIPMENT 


21 


Fig. 7. Bar Magnet 


It is thought to have been 



Fig. 8. Horseshoe Magnet 


century that the discovery was made that a suspended magnet 
would assume a north-and-south position. Because of this prop¬ 
erty, natural magnets came to be known as lodestones (leading 

stones); and magnets, either arti- __ 

ficial or natural, began to be ~5 
used for determining directions. 

The first mention of the use of 
a compass in Europe was in 1190. 
introduced from China. 

x\rtificial magnets are now 
made either by repeatedly strok¬ 
ing a bar of steel, first from the 
middle to one extremity with 
one of the ends, or poles, of a 
magnet, and then from the mid¬ 
dle to the other extremity with the other pole; or else by passing 
electric currents about the bar in a manner to be described later. 
The form shown in Fig. 7 is called a 
bar magnet, that shown in Fig. 8 is a 
horseshoe magnet. 

Poles of a Magnet. If a magnet 
is dipped into iron filings, the filings 
are observed to cling in tufts near the 
ends, but scarcely at all near the mid¬ 
dle, Fig. 9. These places near the 
ends of the magnet, in which its 
strength seems to be concentrated, 
are called the poles of the magnet. 

It has been decided to call the end 
of a freely suspended magnet which 
points to the north, the north-seek¬ 
ing, or north pole, and it is commonly 
designated by the letter N. The other 
end is called the south-seeking, or 
south pole, and is designated by the letter S. The direction in 
which the compass needle points is called the magnetic meridian. 

Laws of Magnetic Attraction and Repulsion. In the experiment 
with the iron filings no particular difference was observed between 




Fig. 9. Location of Poles of a 
Magnet 









































22 


ELECTRICAL EQUIPMENT 


the action of the two ])olcs. That there is a difference, however, 
may be shown by experimenting with two magnets, either of which 
may be suspended. Fig. 10. If two N poles are brought near each 
other, each is found to repel the other. The S poles likewise are 
found to act in the same way. But the N pole of one magnet is 
found to be attracted by the S pole of the other. The results of 
these experiments may be summarized in the general law: Magnet 
poles of like kind repel each other, while poles of unlike kind attract. 

This force of attraction or repulsion between poles is found, 
like gravitation, to vary inversely as the square of the distance 
between the poles; that is, separating two poles to twice their original 
distance reduces the force acting between them to one-fourth its 

original value, and separating them three 
times their original distance reduces the 
force to one-ninth its original value, etc. 

Magnetic Substances. Iron and 
steel are the onlv common substances 
which exhibit magnetic properties to a 
marked degree. Nickel and cobalt, how¬ 
ever, are also attracted appreciably by 
strong magnets. Bismuth, antimony, 
and a number of other substances are 
actually repelled instead of attracted, 
but the repulsion is very small. Until 
quite recently, iron and steel were the 
only substances whose magnetic prop¬ 
erties were sufficiently strong to make 
them of any value as magnets. Ilecently, however, it has been 
discovered that it is possible to make rather strongly magnetic 
alloys out of non-magnetic materials. For example, a mixture of 
05 per cent copper, 27 per cent manganese, and 8 per cent aluminum 
is rather strongly magnetic. These are known as the Ilenssler alloys. 

Electromagnets. The identity of magnetism with electricity 
is readily established by some very simple experiments that have 
been repeated so often as to become classics. By taking a bar of 
iron and winding some insulated wire around it in the form of a 
eoil and then connecting the terminals of this coil with a battery 
or other source of current, the bar becomes magnetic. One end 



Fig. 10. Experiment Proving the 
Law of Magnetic Attraction 
and Uepul.sion 


I 










ELECTRICAL EQUIPMENT 


23 


of it is the positive, plus, or north pole of the magnet, and the other 
the negative, minus, or south pole. Break the connections or 
otherwise “open the circuit” and the magnetism instantly dis¬ 
appears. Reverse the connections to the battery by attaching 
the wire previously at the positive pole to the negative, and vice 
versa, complete the circuit again, and the bar is once more magnetic, 
but now the pole that was previously north or positive is south. 
The bar is once more a magnet, but its polarity has been reversed 
by reversing the direction of flow of the magnetizing current. This 
bar of iron with a coil of wire wound around it is known as an electro¬ 
magnet because it becomes magnetic only when a current is passing 
through the coil. If a rod of hard steel is substituted for the bar 
of soft iron and the current passed through it, the bar will be found 
to be strongly magnetic after the current has been shut off. That 
is, the bar of steel has, through the action of the current, become 
a permanent magnet like that shown in Fig. 7. This method is 
often used for making permanent magnets from hardened steel. 

To determine the polarity of a magnet it is only necessary 
to hold a small pocket compass near it; let the compass needle 
come to rest normally and then bring the compass near to one 
end of the magnet. If the needle continues to point in the same 
direction and gives evidences of being strongly attracted to the 
magnet, the end to which it is being held is the south pole. Bring 
the compass near to the other end of the magnet, and the needle 
will turn away sharply, showing that like poles repel each other. 

Magnetic Field. If a bar magnet is placed on a sheet of glass 
and a handful of flue iron filings thrown- around it, they will auto¬ 
matically assume the position shown by Fig. 11. As originally 
dropped on the glass some of the filings may not be within reach 
of the influence of the magnet, but if the glass be gently tapped 
and tilted slightly, first one way and then another, they will arrange 
themselves in the symmetrical pattern shown. This gives a graphic 
illustration of the field of influence of the lUc^gnet, usually termed 
the magnetic field. This field is most powerfu.. at the poles, as 
will be noted by the attraction of the filings at the i ^ and S points, 
representing the north and south poles of the magneu At inter¬ 
mediate points along the length of the magnet the filing; will be 
seen to havq placed Uiemselves as if to indicate a circular moveiv::?nt 






24 


ELECTRICAL EQUIPMENT 


of the lines of force. This is the magnetic circuit and these concentric 
circles represent the magnetic flux, or flow. If the magnet is then 
removed from the glass and the north pole extension of it placed 



Fig. 11. 


Field of Force about a Bar 
Magnet 



Fig. 12. Field of Force about a Single 
Pole 


centrally under the glass, a striking illustration is given of the 
magnetic field around the pole. Fig. 12. A bar magnet has been 
shown here for purposes of simplicity, but a common horseshoe 
magnet such as can be had for a few cents will serve equally well 
for the experiments. 

By carrying the experiments a little further, the identity of 
magnetism and electricity is strikingly shown. Take a piece of 



cardboard cr heavy paper, punch a hole through its center and 
pass through this hole a wire connected to two or three dry cells. 
S<^Cttier on the paper the filings used in the p|revious experiments, 


























ELECTRICAL EQUIPMENT 


9'i 

then complete the circuit by touching tlie end of the wire to the 
other terminal of the battery. The filings will immediately arrange 
themselves as shown in Fig. 13, illustrating the magnetic field 
which is always present around any current-carrying conductor. 

Lines of Magnetic Force. Punch another hole through the 
cardboard and rearrange the circuit of the dry cells so that the wire 
passes from the positive battery terminal up through one hole 
of the cardboard and down through the other hole to the zinc or 
negative. Scatter the filings as before and touch the loose end 
of the wire to the negative terminal. The arrangement of the 
filings will then be that shown in Fig. 14, the positive field being 
at the left and the negative at the right. The fact that the mag¬ 
netic fields overlap in the curious 
alignment indicated is simply 
due to the proximity of the con¬ 
ductors carrying the current. 

Another simple method of 
demonstrating the identity of 
electricity and magnetism is to 
place an ordinary pocket com¬ 
pass near a wire carrying a cur¬ 
rent. If this is a direct current 
and the needle of the compass 
whirls around when its north 
pole is presented to the wire, it is evidence that the current in the 
wire is positive, since like poles repel. Present the other end of the 
needle and it will remain stationary even though tlie compass be 
shaken, since unlike poles attract. This experiment is accordingly 
a simple polarity test as well. 

All of the arrangements which the filings assume under the 
influence of either a magnet or a current, as shown by the various 
llustrations, indicate that the stresses in the medium surrounding 
a magnet or current-carrying conductor follow certain definite 
lines, the lines showing the direction of stress at any point. These 
are termed lines of force. 

Solenoids. It has been determined that the direction of the 
current and that of the resulting magnetic force are related to one 
another as the rotation and travel of an ordinary, or right-hand, 



Fig. 14. Field about a Coil 






20 


ELECTRICAL EQUIPMENT 



Fig. 15. 


Direction of Magnetic Lines about a 
Conductor 


screw thread. Consequently, if the conductor be looped instead 
of straight, the lines of magnetic force will surround it as shown 
in Fig. 15. The field of such a loop, if outlined with the aid of 
filings or explored with a compass needle, will be seen to retain 

the general character of 
the field surrounding a 
straight conductor, so 
that all the lines will 
leave by one face and 
return by the other, the 
entire number passing 
through the loop. Hence one face of the loop will be equivalent 
to the north pole of a magnet and the other face to the south 
pole. In fact, the loop will act exactly as if it were a thin disk 
magnetized perpendicularly to the plane. By winding a number 
of these loops to make a hollow coil, there is formed a solenoid. 
Fig. 16. Exploring its field shows that the lines of force pass 
directly through the center or opening of the hollow coil, leaving 
by one end and returning by the opposite end, as indicated. 

If such a solenoid is held vertically and a bar of soft iron placed 
so that it extends for an inch or so into the lower end of the solenoid, 
a current passed through the latter will cause the iron to be violently 
drawn up into the coil and held there. As long as the current 
flows, this rod is strongly magnetic and has all the properties already 

described. But the mo¬ 
ment the current is shut 
off, the magnetisni prac¬ 
tically disappears and 
the rod immediately 
drops out of the coil by 
its own weight. Re¬ 
versing the direction of 
the current reverses the 
polarity of the solenoid; 
increasing or decreasing the amount of current sent through it 
increases or decreases correspondingly the strength of its magnetic 
field. The principle of the solenoid is used in starting systems 
to operate electromagnetic starting switches. 





































ELECTRICAL EQUIPMENT 


27 


Effect of Iron Core on Strength of Solenoid. The iiiagnetic 
flux or flow of lines of force through a solenoid is much greater 
when an iron core is present than when the coil is empty or a core 
of wood is inserted. The magnetism flows through the iron as a 
current would. Soft iron is said to have a high magnetic immea- 
hility. The magnetic permeability of air (or a vacuum) is taken 
as unity and other substances rated accordingly: for very soft iron 
it may be as high as 2500, while for substances such as silk, cotton, 
wood, glass, brass, copper, and lead, it is unity, the same as for air. 
Such metals are said to be non-magnetic. All insulators are 
likewise non-magnetic. 

INDUCTION PRINCIPLES IN GENERATORS AND MOTORS 

Induction. When a wire carrying a current is placed close 
to another wire, a delicate measuring instrument such as a galva¬ 
nometer will indicate the presence of a current in the second wire. 
When the current in the first wire ceases, that in the second will 
likewise cease immediately. This phenomenon is known as induc¬ 
tion, and a current is said to have been induced in the second wire. 

Winding the first wire in the form of a coil and bringing this 
coil close to the second wire, will give the induced current con¬ 
siderably greater strength. The induced effect is still further 
increased in three other ways: first, by inserting an iron core in the 
coil; second, by winding the second wire in the form of a coil; and, 
third, by bringing these coils as close togetlier as possible by winding 
one directly over the other. 

Transformer Principle. The arrangement just discussed is 
termed an induction coil or transformer (step-up) and is universally 
employed in connection with ignition systems. The character 
of the induced current depends upon the relation that the first 
coil, termed the primary, bears to the second coil, known as the 
secondary. In the usual ignition coil the primary consists of a 
few turns of comparatively heavy wire, and a heavy current 
10 to 20 amperes or more—is sent through it at a low voltage, one 
seldom exceeding 6 volts. The secondary coil, however, consists 
of a great number of turns of exceedingly fine wire, and the current 
induced in this is proportional to the relative number of turns 
between the two and the value of the current in the primary. The 


28 


ELECTRICAL EQinPMENT 


secoiulary current is accordingly of extremely high potential but 
of only nominal current value. 

In the commercial step-down transformer, the relations described 
above are reversed, the primary being a coil of many turns of fine 
wire, while the secondary is a comparatively small coil of few turns. 
In this case, the current is received at the transformer at high 
voltage and correspondingly reduced amperage, and it steps the 
voltage down to the standard generally employed, 110 or 220 volts, 
and increases the amount of current proportionately. 

SeIf=Induction. It has already been pointed out that electricity 
may be put under pressure or potential, and that the greater this 
pressure, the greater the amount of work a certain amperage of 
current will perform, thus affording a direct analogy with steam, 
water, or air under pressure. An electric current also possesses 
other characteristics corresponding to mechanical equivalents. 
Chief among these is inertia and it is the latter that is responsible 
for what is known as self-induction. 

When a current is passed through a coil of wire, a strong magnetic 
field is set up in the coil owing to the concentration of a great many 
turns of wire in a small compass. By inserting a core of soft iron 
wires into this coil, the magnetic field is greatly strengthened, since 
the permeability of the iron affords a path of slight resistance for 
the magnetic circuit. There is, of course, a magnetic field sur¬ 
rounding every conductor in a circuit when the current is passing, 
but the iron core of the solenoid converts a certain part of this 
current into magnetism. An appreciable time is necessary after 
the circuit is closed for such a coil ‘‘to build up”. This “building 
up” consists of saturating the core with magnetism. 

When the circuit is suddenly opened, the current that has been 
stored in this core in the form of magnetism is as quickly retrans¬ 
formed and its value is impressed upon the circuit, causing a flash 
at the break. The flash is also aggravated by a certain amount 
of inertia which the current possesses. We may illustrate this 
by a stream of water flowing in a pipe. If the water is suddenly 
shut off by the closing of a valve, it tends to keep on flowing and 
momentarily causes a great increase in the pressure against the 
face of the valve, resulting in the familiar “water hammer”. The 
same thing happens when a circuit is suddenly broken, and the 


ELECTRICAL EQUIPMENT 


29 


higher the potential the more marked this effect will be. The 


current tends to keep on flowing, and the extra potential which 
this self-induction gives it will cause it to arc, or bridge, the gap at 
the break, unless a condenser is provided to take care of this. Every 
circuit possesses self-induction, but it is only marked in circuits 
having considerable inductance, that is, in coils, and especially those 
with iron cores, such as induction coils, circuit breakers, etc. 

Capacity of Condensers. Every conductor of electricity has 
capacity to hold a charge just as a vessel holds water. But the 
capacity of a conductor is dependent upon its surface area rather than 
its cross-section, or cubic volume, and is also influenced by surround¬ 
ing conditions. Where it is desired to accumulate a considerable 
charge, as for an ignition spark, a special form of capacity is utilized, 
ddiis is known as a condenser (a detailed description of which is 


given later in connection with ignition coils). The ability of a 
condenser to absorb the rise in potential that occurs through self- 
induction whenever a circuit containing inductance is opened is 
also utilized to prevent sparking at contact points. Comparatively 
small condensers are necessary for this purpose, and they are shunted 
around the contact points, that is, connected in parallel witl^ the 
latter. When the circuit is opened the excess energy of the circuit 
passes into the condenser instead of forming a hot spark at the 
contacts. The occurrence of any undue amount of sparking at 
contacts should accordingly be made the subject of an investigation 
of the condenser connections, or of the condenser itself. 

Comparison of Generator Current to Water Flow. The com¬ 
parison of air in a room has been made to illustrate the presence 
of electricity and its characteristics, since it may be made to partake 
of all the latter by being put under pressure, allowed to escape 
through various sized outlets, and made to perform work of differing 
nature by being utilized at varying pressures and volumes, exactly 
as electricity is. Where an electric current is produced by a gener¬ 
ator, however, the older simile of water flowing under pressure due 
to the impulse of a pump may serve to make it much clearer. 
This comparison of a water pump and its piping with an electric 
generator and its circuits is known as a hydraulic analogue, and, it 
may be added, there is scarcely any characteristic or function of 
the electrical current that cannot be similarly compared. 


30 


ELECTRICAL EQUIPMENT 


Take, for example, a waterworks system of the type in which 
a large pump at the power house draws water from artesian wells 
or a reservoir and forces it into a closed system of piping. Located 
on this piping system are all the house outlets, street hydrants, and 
the like. The speed of the pump is regulated so as to keep a certain 
amount of pressure on the water in the pipes, based upon the average 
demand at different periods of the day. The pressure is reduced at 
night and is increased at any time, day or night, in case of fire. 

Pressure and Voltage. This constant pressure in pounds per 
square inch that the pumps maintain on the supply of water in the 
entire piping system is the exact counterpart of the voltage, or electro¬ 
motive force, produced by a dynamo, or generator, when running. 
Just as the pressure exerted on the water by the pumps depends 
upon the speed of the latter, so the voltage produced by the dynamo 
is proportional to its speed. In the case of the pump, the pressure 
depends upon the number of times that the pistons of the puin]) 
reciprocate; in the dynamo, upon the number of times that the 
coils, or windings, of the armature cut the lines of force of the mag¬ 
netic field in which it revolves. This is explained in detail later 
in connection with generator principles. 

When the pump moves very slowly, there is very little pressure 
produced in the pipes, and this is the case with the dynamo to an 
even greater extent, since dynamos are usually designed to run at 
very much higher speeds, and consequently their voltage, or pressure, 
drops off very sharply at low speeds. This will explain why the 
majority of lighting generators on automobiles do not begin to charge 
the battery until the motor of the car is running at a speed equiva¬ 
lent to ten to fifteen miles per hour, as explained later. At low 
speeds they do not generate sufficient voltage to overcome that of 
the battery. 

Fall in Pressure. When either a pump or a dynamo is running 
at a constant speed, the pressure, or voltage, produced at the machine 
is practically constant. But in the case of the water system, the 
pressure is not the same at the outlet of a branch line a mile away 
from the power house as it is at the delivery end of the pump, nor 
is the voltage on a branch circuit at a great distance from the dynamo 
the same as it is at the terminals of the latter, consequently, 
the fall in pressure in the water piping is the exact counterpart of 


ELECTRICAL EQUIPMENT 


31 


the drop in voltage on the electric circuit due to the resistance of 
the wires. In the case of the water supply, the friction encountered 
by the water in passing through the pipes is analogous to the resist¬ 
ance which the electric current must overcome, except that bends 
in a wire do not impose any greater resistance to the current than 
the same length of wire when straight, whereas bends in piping greatly 
add to the friction with a correspondingly greater drop in pressure. 

Friction and Resistance. There is, in consequence, almost an 
exact parallel between the mechanical friction of water passing 
through a pipe and that of the electric current passing through a 
wire, as it is commonly said to do. Friction in water piping is 
inversel}^ proportional to the size of the pipe in proportion to the 
l)ressure to which the water is subjected, and is directly proportional 
to the length of the pipe in exactly the same way that a wire opposes 
more resistance to the electric current the smaller the wire is, and 
the amount of resistance also increases with the length of the wire 
itself. In both cases, the product of this friction, or resistance, is 
heat; and it results in a drop in pressure, whether mechanical or 
electrical. 

Current and Volume. So far the comparison has been limited 
entirely to the pressure exerted by the pump on the supply line as 
compared with the voltage of the generator imposed on the circuit. 
In a similar way the flow of water from the pipe line may be compared 
with that of the current in an electrical circuit. Assume, for example, 
that, in the case of the water-supply system, the pumps generate a 
pressure of 100 pounds to the square inch. Eliminating from con¬ 
sideration any drop in pressure between the pump and outlet as 
only tending to confuse the comparison, suppose a half-inch faucet 
to be opened at a distant part of the system. Then there will flow 
from the pipe an amount of water proportioned to the size of the 
outlet times the pressure, or head, back of it. Let us assume that 
this will be one cubic foot per minute, or, roughly, eight gallons. 

In the same way, assume that the generator imposes a pressure 
of 100 volts on the line and, for purposes of comparison, there is 
no drop between the generator and the end of the line. So long as 
there is no outlet open there is pressure on the water in the supply 
system, but no flow. This is likewise the case with the electric 
circuit. The voltage is present as long as the armature of the dynamo 


32 


ELECTRICAL EQUIPMENT 


is revolving, but there is no flow of current in the circuit. A small 
fan motor, corresponding to the half-inch faucet, is. switched on at 
a distant part of the circuit. There is then a flow of current of, 
say one ampere. In this case, the hydraulic analogue reflects exactly 
the action of the current as compared with the water supply in a 
pipe. If, instead of opening a small house faucet, we open the valve 
of a branch main a foot in diameter, there is a correspondingly greater 
volume of water flowing, but the pressure remains the same. On the 
other hand, if, instead of a small fan motor, a five-horsepower motor 
is switched into the circuit, the outflow of current will be equivalent 
to five horsepower, though the voltage of the circuit will remain 
the same. (There is, of course, always a voltage drop with every 
I)iece of apparatus that the current passes through before com- 
})leting the circuit by returning to the generator, just as there is a 
drop in water pressure for every additional length of pipe or open 
outlet in the system; but, to keep the comparison clear and simple, 
this is not taken into consideration here.) Thus, in one case, we 
have one cubic foot [of water per minute flowing under a head, or 
pressure, of 100 pounds per square inch; in the other, a current of 
one ampere at a voltage of 100; also the fact that the volume of 
either water or electricity that will flow depends upon the resist¬ 
ance of the outlet. The fan motor is wound to a high resistance, 
and, consequently, only one ampere of current is required to 
operate it at its maximum speed. In the same way, the i-inch out¬ 
let will permit only one cubic foot of water to escape per minute. 
Increasing the size of the outlet in either case increases the flow 
correspondingly. The simile holds good with the water system 
up to the point where the outlet becomes too large to permit the 
pumps to maintain the pressure; but, in the case of the electric 
generator, the resistance cannot be decreased to zero, since this 
would result in a short-circuit permitting the entire current output 
of the dynamo to flow. Unless the dynamo were protected by cir¬ 
cuit breakers and fuses, the functions of both of which are explained 
later, the windings of the machine would be burned out. 

Power Comparison. To go back to the simile between water 
and current flow, it will be noted that in one case there is a flow 
of one cubic foot per minute at 100 pounds to the square inch, and, 
in the other, a flow of one ampere of current at 100 volts. This 


ELECTRICAL EQUIPMENT 


33 


flow of water represents power just as the flow of electric current 
does, and it may be utilized in a similar manner. The product of 
the volume times the pressure would give foot-pounds in the case 
of the water and watts in the case of the electrical energy, in 
other words, one ampere times 100 volts, or 100 watts—almost 
one-seventh of a horsepower. 

Circuits. The simile of the water-supply system does not 
correspond exactly to any type of electric circuit, in that the water 
does not return to the pump in any case, as the current always must 
to the generator, to complete the circuit. But it does afford a com- 
})arison of the characteristics of both series and multiple circuits, 
showing to what an extent the illustration of electrical principles 
may be carried by means of a simple mechanical analogue. For 
instance, the opening of one outlet after another in a water system 
reduces the pressure in the entire system, just as the insertion of 
one piece of apparatus after another in a series electric circuit 
causes a corresponding drop in voltage for each addition, except, 
of course, that in case of the series electric circuit it must alwavs 
be complete, regardless of whether one or a dozen different pieces 
of apparatus be included in it. In other words, the current must 
pass through each one of them in turn to complete the circuit. On 
the other hand, the water system has some of the characteristics 
of a multiple, or parallel, electric circuit, in that the opening of one 
outlet does not prevent the use of others, whereas in the series circuit, 
the breakdown of one piece of apparatus, such as a motor or a lamp, 
puts all the others out of action by opening the circuit. 

The comparison may be carried still further to illustrate other 
attributes of the electric circuit. For example, if there be a bad 
break in one of the large mains of the water system, no water will 
reach smaller outlets beyond the break in the main, the entire volume 
flowing out of this opening. This corresponds very closely to a 
ground or short-circuit on an electric circuit. If one of the wires, 
instead of carrying the current to the motors, permits its supply to 
return to the generator by a shorter path, due to faulty insulation 
or a broken wire touching the ground, no useful work will be per¬ 
formed by the current. It will escape and be wasted just as the 
water is, with this important difference, however, that in the 
case of the water pumps, the break in the main will be evidenced 





34 


ELECTRICAL EQUIPMENT 



Fig. 17. Elementary Principle of Generator 


only by a marked decrease in the pressure, and the pumps will run 
to no purpose, whereas the electric generator will still continue to 
generate its full voltage, and, unless the grounded circuit caused by the 

break has sufficient resistance, 
the circuit breaker, or fuses, 
must operate to protect it. 

GENERATOR PRINCIPLES 

Classification. All dy¬ 
namo-electric machines are 
commercial applications of 
Faraday’s discovery of in¬ 
duced currents in 1831. They are all designed to transform the 
mechanical energy of a steam engine, a waterfall, a gasoline engine, 
etc., into the energy of an electric current. Whenever large currents 
are required—for example, in running street cars; in systems of 
lighting and heating; in the smelting, welding, and refining of metals; 
the charging of storage batteries, etc.—they are always produced 
bv dvnamo-electric machines. 

t t/ 

There are two kinds of generators (1) d.c., or those producing a 
unidirectional (direct) current, that is, one which always fiows in 
the same direction in the external circuit, and (2) a.c., or those 
])roducing an alternating current, that is, one which reverses in 
direction continuously throughout the entire circuit. 

Elementary Dynamo. Whenever lines of magnetic flux are cut by 
a conductor, for example, by a wire passing through them, an e.m.f. 
felectromotive force) is produced in the conductor, and the strength 
of this e.m.f. is entirely dependent- upon the speed at which the 
conductor passes through the magnetic field. If, at the time that 
this is done, the ends of the wire are brought together to form a 
circuit, a current will be induced in the conductor. The simplest 
form of generator would consist of a single loop of wire ABCl) 
arranged to rotate in a magnetic field, as shown by Fig. 17. Having 
its plane parallel to the direction of the magnetic flux, the loop, if 
it be rotated to the left as shown, will have an e.m.f. induced in it 
that will tend to cause a current to flow in the direction shown bv 
the arrows. The e.m.f.’s induced in AB and Cl) for the position 
shown will have their maximum values since the wires are then cut- 



















ELECTRICAL EQl'lPMENT 


*> ^ 

oo 


ting the magnetic flux at right angles and are consequently cutting 
more lines of force per second than in any other part of the revo¬ 
lution. Note that as CD moves up, AB moves down (and vice 
versa) across the magnetic flux so that the induced currents ih all 
parts of the loop at any instant are 
flowing in one direction. The value 
of this e.m.f. depends upon the 
speed, and as the loop approaches 
the 90-degree, or vertical, position, 
the e.m.f. decreases because the rate 
of cutting is diminishing, until when 
the loop is vertical both the cutting 
of the magnetic flux and the generated e.m.f. are at zeto. If the rota¬ 
tion is continued, the rate again gradually increases, until at 180 
degrees it is once more a maximum. The cutting, however, in the two 
(juadrants following the 90-degree position has been in the opposite 
direction to that occurring in the first quadrant, so that the direction 




Fig. 19. Simple Form of Generator Showing Arrangement of Brushes 
in Contact with Commutator 


of the e.m.f. generated is reversed. Plotting this through an entire 
rotation gives the curve shown in Fig. IS. Such an e.m.f. is termed 
alternating because of its reversal from positive to negative values, 
first in one direction and then in the other, through the circuit. 
It cannot be utilized for charging a storage battery, and hence it 
is not employed in connection with starting and lighting dynamos 
and motors. To convert an alternating current into a direct or 
continuous current, a commutator must be added. 

Commutators. Fig. 19 illustrates a commutator in its simplest 
form. It may be imagined as consisting of a small brass tube 
which has been sawed in two longitudinally, the halves being mounted 

























30 


ELECTRICAL EQUIPMENT 



Fig. 20. Commutator with Double Turn 


on a wooden rod. The wood and the two cuts in the tube insulate 
the halves from each other. Each one of these halves is connected 
to one terminal of the loop, as shown in the illustration, Fig. 20. 
Against this commutator. Fig. 

19, two brushes bear at opposite 
points and lead the current due to 
the generated e.m.f. to the ex¬ 
ternal circuit. If these brushes 
are so set that each half of the 
split tube moves out of contact 
with one brush and into contact 
with another at the instant when 
the loop is passing through the 
positions where the rate of cutting is minimum (as indicated in 
the enlarged end view of the commutator shown at A), a unidi¬ 
rectional current will be produced, but it will be of the pulsating 
character as indicated by the curve for one cycle shown in Fig. 21. 

This would also be the case, 
if instead of the single loop, a coil 
wound on an iron ring be substi¬ 
tuted, as in Fig. 22, the only effect 
of this being to increase the e.m.f. 
by increasing the number of times 

the electrical circuit cuts the magnetic flux. Now assume that two 
coils are connected to the commutator bars, instead of the single 
loop, shown in Fig. 22. This arrangement will give the simple 
device shown in Fig. 23, called an armature. The two coils are 





in parallel and while the voltage generated by revolving this winding 
with two coils is no greater than with one coil, the current-carrviinr 
capacity of the winding is doubled. The current generated by 





























ELECTRICAL EQUIPMENT 


this form of armature woukl still have the disadvantage, however, 
of being pulsating. As in the case of the automobile motor, the 
number of cylinders must be increased to make the power output 

a continuous unbroken line, so 
armature coils and their corre¬ 
sponding commutator brushes 
must be added that one set may 
come into action before the other 
‘‘goes dead”. By placing an 
extra pair of coils on the arma¬ 
ture, at right angles to the first, 
as shown in Fig. 24, one set will 
be in the position of maximum activity when the other is at the point 
of least action. While this armature would produce a continuous 
current, it would not be steady, having four pulsations per revolu¬ 
tion, and it is consecpiently necessary to increase the number of 
coils and commutator segments still further to generate a steady, 
continuous current. This is what is done in practice. 

A commutator consists of a number of copper bars or segments, 
equal to the number of sections in the armature. These bars aie 
separated by sheets of insulating material, usually mica, and are 



Fig. 24. Four-Coil Armature 



Fig. 25. Sectional and End Views of a Commutator 
Courtesy of Horseless Aye 


firmly held together by a clamping device consisting of a metal 
sleeve with a head having its inner side undercut at an angle, a 
washer similar in shape to the head of the sleeve, and a nut that 































ELECTRICAL EQUIPiMENT 




screws over the eiul of the slee\’e, as shown in tlie left-hand or 
sectional view of Fig. 25. The sleeve is snrroundeHl by a bushing 
of insulating material, and washers of the same material are placed 
between the assembly of commutator bars and the two clamping heads. 
Each bar is then completely insulated from every other bar and from 
the clamping sleeve. Commutators are also made by pressing the 
entire assembly of copper segments together, or molding them, 
in insulating material (Bakelite), which thus forms the hub or 
mounting of the commutator as well as the insulating material 
betw^een the segments. After assembling, the commutator is 
turned down in a lathe to a true-running cylinder and then sand¬ 
papered on its outer cylindrical surface to present a smooth bearing 
surface for the brushes. At the inner end of the commutator 
which is closest to the armature windings, the commutator bars 
are provided with lugs as shown in the sectional view; these lugs 
are slotted and the armature leads are soldered to them. At the 
right. Fig. 25, is shown an end view of the same commutator. 

From the repair man’s point of view, the commutator is the 
most important part of the generator or the motor, since it is one 
of the first with whose shortcomings he makes acquaintance. Prac¬ 
tically all lighting and starting motors now have their armature 
shafts mounted on annular ball bearings, so that the commutator 
and the brushes are the only parts that are subject to wear. If 
the time devoted in the garage to the maintenance of automobile 
electric systems were to be divided according to the units demanding 
attention, the battery would naturally come first, brushes and 
commutators next, then switches, regulating instruments, con¬ 
nections, and wiring, about in the order named. After all of these 
come, of course, burnt-out armatures or other internal derangements 
which necessitate returning the units to the manufacturer; but 
troubles of this nature are quite rare. While this list gives the 
order of precedence, it has no bearing on the relative importance 
of the troubles; with respect to the total time taken by each, the 
battery is responsible for not far from 90 per cent, the commutator 
for about 5 per cent, all other causes comprising the remaining 5 
per cent. 

Armature Windings. In the simple illustrations given to 
show the method of generating e.m.f. in the armature and leading 


ELECTIUC^AL EQUIPMENT 


39 


the current to the external circuit, what is known as the ring type 
of winding is shown. This is inefficient because half the length 
of the conductor—the portion inside the ring—does not cut any 
lines of force and hence does not aid in generating the current. 
The design, moreover, does not lend itself to compactness, so that 
it would not be adapted to automobile work even if there were no 
objection to it on the score of inefficiency. A slotted type of arma¬ 
ture core is very generally employed for the small generators and 
starting motors used on automobiles and the wire is either wound 
directly in the slots, or is ^‘form wound”, that is, the wire is placed 
on a wooden form shaped to correspond to the position the coil will 
take when in place on the armature. After winding the necessary 
length of conductor on this foundation, the wire is taped together, and 
varnished or impregnated with an insulating compound, and baked. 

Owing to its high magnetic permeability, iron is universally 
employed for the core of the armature, since the function of the 
core is to carry the magnetic flux across from pole to pole of the 
field magnets, as well as to form a foundation for the coils. How¬ 
ever, when a mass of iron is rotated in the field of a magnet what 
are known as “eddy currents” are set up in the metal itself, and 
these prevent the inner parts of the mass from becoming magnetized 
as rapidly as the outer and also cause the interior to retain its mag¬ 
netism longer. As the efficiency of the generator depends upon 
the rapidity with which the sections of the armature become mag¬ 
netized and demagnetized as they revolve, the lag due to these eddy 
currents is a detriment. To reduce this effect to the minimum, 
the armature cores are always laminated, that is, built up of thin 
disks of very soft iron or mild steel, these disks having the necessary 
slots punched in them to accommodate the windings when assembled 
on the shaft. The disks are insulated from one another either by 
varnishing them or by inserting paper disks between them. They 
are assembled on the shaft and are put together under considerable 
pressure, various means being employed to hold them in place. 
These disks are so thin that hundreds of them are required to make 
an armature core only a few inches long, and when pressed together 
in place they are to all intents and purposes a solid mass. 

Armature winding, however, is something that is entirely 
beyond the province of either the car owner or the repair man, no 


40 


ET.ECTRICAL EQUIPMENT 


matter how well equipped a shop he has. It is a job for the expert 
in that particular line, and on the rare occasions when an armature 
does go wrong, it should always be returned to the manufacturer, 
if possible, if not, to a shop making a 
speciality of such work. 

Field Magnets. In the foregoing 
explanation of the generation of an 
e.m.f. in a conductor when rotated in a 
magnetic field and the leading out of 
the current through a commutator, the 
presence of the field has been assumed 
and nothing has been said regarding 
the method of providing it. The term 
field is applied interchangeably to the 
magnetic flux between the pole faces of 
the field magnets and to the magnets 
themselves, but it is more generally 
understood to refer to the latter directly 
and to the former by inference. There 
are various methods of maintaining 
the flux, usually described as ‘Tield magnet excitation”, but only 
two of them are applicable to the electric generators employed on 
the automobile. 

Permanent Field Used in Magneto. The simplest of these, 
and the first to be designed, employed permanent magnets, from 
which such a generator takes its name, 
magneto. Fig. 26 is a diagrammatic rep¬ 
resentation of an early form of the mag¬ 
neto-generator. Since magnetism cannot 
be maintained permanently at the high 
flux-density or strength which can be 
produced by an exciting coil fed by a 
current, this method is only employed 
in very small generators, as its bulk for 
large powers would be excessive. Its 
great advantage is its simplicity and constancy. The magneto-gener¬ 
ator shown in Fig. 26, however, is designed to produce a continuous 
current, and is not the type in general use on the automobile today. 




Fig. 


27. Sketch Showing Shape of 
Armature Core 
Courtesy of Horseless Age 
























ELECTRICAL EQUIPIMENT 


11 


The type usually installed is made with a two-pole armature, 
as shown by Fig. 27. This figure illustrates the core known as 
a ‘^shuttle” type because the wire is wound around the center of 
the core in much the same manner as thread is put on a shuttle. 
These cores are laminated as already described, in all well-built 
magnetos. The space on the core is filled with a single coil of 
comparatively coarse wire on the majority of magnetos, which 
generate a low voltage current that is subsequently stepped up 
through an outside transformer. In some instances, in what may be 
termed the true high-tension type of magneto, there is a second wind¬ 
ing of fine wire on the core so that the magneto generates a current 



Fig. 28. Diagrams Showing Distribution of Alagnptic Flux for Various Positions 

Courtesy of Horseless Aye 

and steps it up without the aid of any outside devices. In either 
case, one end of the winding is “grounded on the core”, that is, 
connected to it electrically, so that the core and other metal parts 
of the machine form one side of the circuit, while the other end is 
connected to a stud against which a spring-controlled carbon brush 
l)ears, to collect the current. Detailed descriptions of various 
types of magnetos are given later so that nothing further concerning 
the construction need be added here. 

Principle of Operation of Magneto. Under “Generator Prin¬ 
ciples”, the principle of the operation of the magneto has already 
been explained, the method by which the rotation of the conductors 
in the magnetic field generates an e.m.f. and a current is induced 





















12 


ELECTRICAL EQUIPMENT 


in them. But as the actual operation of the magneto as designed 
for ignition purposes is radically different from any other form of 
generator, it is given here. If unrestricted, the armature of the 
magneto will always assume the position shown at A, Fig. 28, and 
considerable effort will be required to turn it from this position 
as the magnetic flux through the armature is then a maximum. 
When the armature is rotated a little over 90 degrees from this 
horizontal position so that the armature poles leave the field poles, 
as at B in the same figure, the flux decreases, and when in a vertical 
position no lines of force pass through it. At this point, the direction 


n 






n 



H 


m 


H 




H 



Fig. 29. Curve of Primary E. IM. F. in Magneto on 
Open Cireuit 

Courtesjj of Horseless Age 

of the magnetic flux through the armature core reverses. Having 
a two-pole armature, the magneto produces an alternating current 
of two complete cycles per revolution, as shown by the curve, Fig. 
29, which illustrates the electromotive force generated at the dif¬ 
ferent positions in the rotation of the armature. The similarity 
between this curve and the one generated by the elementary dynamo. 
Fig. 17, will be noted. With the armature in the horizontal position 
there is a dead point, the e.m.f. curve only starting as the pole 
pieces of the armature begin to cut the edges of the field magnet 
poles. It then rises very sharply to a peak, and as sharply drops 











































ELECTRICAI^ EQUIPMENT 


43 



Fig. 30. Diagram Showing Series Generator 


away to zero again, thus coinpleting one cycle, wliicli is then repeated 
in the op])osite direction. As the present discuSvsLoii comprises 

only an introduction to elemen¬ 
tary principles and theories? 
further details of construction 
and operation of the magneto 
are given later in the section on 
^‘Ignition”. 

Self-Excited Fields. In a 
machine of the magneto type, the 
only method of varying the cur¬ 
rent output is to vary the speed 
of the armature, and it is there¬ 
fore not well adapted to the 
majority of uses for which a gen¬ 
erator is employed. Conse¬ 
quently, other methods of excit¬ 
ing the fields have been developed, which may be roughly divided 
into two classes: first, those separately excited, in which cur¬ 
rent from an independent source is supplied to the field windings. 
This is now practically restricted to large alternating-current gen¬ 
erators and so need not be con¬ 
sidered further here. Second, 
self-excited fields, which are now 
characteristic of all continuous 
current generators. In this 
method all or a part of the cur¬ 
rent induced in the armature 
windings is passed through the 
field coils, the amount depend¬ 
ing on the type of generator. 

Series Generator. Where 
the entire current output is util¬ 
ized for this purpose, the dynamo 
is of the series type, and a refer¬ 
ence to the section on ‘^Cir¬ 
cuits”, in connection with the illustration. Fig. 30, will make this 
plain. There is but a single circuit on such a dynamo and while it 



Fig. 31. 


Diagram Showing Shunt-Wound 
Generator 









































11 


ELECTRICAL E(JUIPiMEXT 


has the advantage of siinplicit}^ it does not generate a current until 
a fairly high speed is reached, or unless the resistance in the 
external circuit is below a certain limit. It is also likely to have 
its polarity reversed so that it is not fitted for charging storage 
batteries. As the only series generators put into commercial use 
have been for supplying arc lamps in series for street lighting^ 
they need not be considered further. 

ShuntAVound Generator. By winding the generator with two 
circuits instead of one and giving that of the fields a relatively high 
resistance as compared with the outside circuit on which the generator 
is to work, a machine that is self-regulating within certain limits 
is produced. As shown by Fig. 

31, the main circuit of the gener¬ 
ator is that through the arma¬ 
ture with which the field wind¬ 
ing is in shunt. The current 
accordingly divides inversely as 
the resistance and only a small 
part of it flows through the field 
coils, while the main out})nt of 
the generator flows through the 
external circuit to light the lamps, 
to charge a battery, or the like, 
the resistance of this external 
circuit being much less than that 
of the fields. But in this type, 
as well as in the simple series form, the e.m.f. generated varies more 
or less with the load, and as the latter is constantlv chaiiiriny:, it 
is necessary to provide some means of varying the e.m.f. gen¬ 
erated to suit the load, in other words, to make the generator 
self-regulating. Of the several available methods of doing this, 
the only one applicable to the small direct-current generators used 
in automobile lighting and starting systems, is that of varying the 
magnetic flux through the armature. 

Compound-Wound Generator. There are also several methods 
of effecting this variation of the magnetic flux, but the most advan¬ 
tageous and consequently the most generally used, is to vary the 
amount of current in the energizing coils on the field magnets. 



Fig. 32. Diagram Showing Compound- 
Wound (Jenerator 




































ELECTRICAL EQUIPMENT 


45 


By adding to the shunt winding a few turns of heavy wire in series 
with the armature so that all the current passes through them, the 
magnetic flux may be made to increase with the load as it is directly 
affected by the current demanded by the latter. This combination 
of the shunt and series is termed a compound winding, and the 
usual method of affecting it is shown by Fig. 32. Such a machine 




Fig. 33. Foriiid of Field Frames 


is called a compound generator, and is the type almost universally 
used for lighting and for charging the storage batteries of auto¬ 
mobiles. In view of the great range of speed variation of the auto¬ 
mobile motor, this compound wiring is sometimes reversed so as 
to act against the shunt instead of with it, in order to prevent an 
excessive amount of flux and a current that would l)e dangerous 
to the windings themselves due to a very high speed. The compound 











































4() 


ELECTRICAL EQUIPMENT 


winding then opposes the shunt-winding and is termed a bucking- 
coil or winding. This is referred to later in connection with the 
discussion of methods of regulating the generator on the automobile. 

Forms of Field Magnets. For greater simplicity, all of the 
illustrations shown in connection with the explanation of the various 
types of generators are of the old bipolar type in a form long since 
obsolete. The field frame, as it is designated may, however, take 
a number of different forms depending entirely upon the designer’s 
conception of what best meets the requirements of ample power 
in the minimum of space and with the minimum weight. Fig. 
33 shows some typical forms of field frames in general use on auto¬ 
mobile generators, and it will be noted that in addition to providing 
a magnetic circuit the field frame also serves to enclose the windings. 
These are known as “ironclad” types from the fact that all parts 
are thoroughly enclosed and protected. The arrows in each case 
indicate the paths of the magnetic circuits, the number of the cir¬ 
cuits varying with the number of pole pieces. The form at A has 
two opposed poles, each of which is designed to carry an exciting 
coil or winding. This is a bipolar machine. Field frame B is 
also of the bipolar type but only one pole carries an exciting winding, 
the other being known as a consequent pole. In both of these 
field frames, it will be noted that the magnetic circuits are long, 
which adds to the magnetic reluctance and tends to decrease the 
efficiency. To overcome this, multipolar types of field frames 
are very generally employed. One of these, with two wound or 
salient poles and two consequent poles, is shown at D, the extra 
poles making four short instead of two long magnetic circuits. 
C is a multipolar type with four salient poles. 

Brushes. Brushes serve to conduct the current generated 
by the armature to the outer circuit and to the field coils in order 
that the excitation of the latter may correspond with the demand 
upon the generator. The brushes originally employed were strips 
of copper which bore on the commutator; as generators increased 
in size these brushes were built up of thin laminations of cop})er. 
Plain copper brushes in any form, however, cause an excessive 
amount of sparking which is ruinous to the smooth surface and 
true running of a commutator. Built-up copper gauze brushes 
were then adopted, and they were fitted to bear against the com- 


ELECTRICAL EQUIPMENT 


47 


inutatar. Though an improvement, these did not meet all the 
requirements and were in turn superseded by carbon brushes, 
which are now practically universal. The carbon brushes usually 
bear directly against the face of the commutator, either through 
a blunt, squared end, or one that is slightly beveled. The brush 
holders are generally bronze castings attached directly to the field- 
frame extensions; in them are placed small helical springs under 
compression, which serve to press the brush against the commutator. 
Ordinarily, the brushes are composed of a uniformly smooth and 
homogeneous compound of carbon that soon acquires a glazed 
surface at its bearing end and wears indefinitely without requiring 
any attention, but at times a gritty brush will be found. Such a 
brush scratches the commutator surface, wears unevenly, and is 
generally a source of trouble. 

Badly worn commutators frequently result from the use of 
improper brushes, or too heavy a spring pressure—also from too 
light a spring pressure. The manufacturer has found out by experi¬ 
ment and study just what character of brush is best adapted to 
his particular generator or starting motor and also the exact amount 
of spring pressure that is necessary to insure the best results. Con¬ 
sequently, much trouble will be avoided if brushes are replaced 
only with those supplied by the manufacturer of that particular 
machine, in connection with the brush springs that were designed 
for it. There are electrical as well as mechanical reasons for this, 
since both the resistance and current-carrying capacity of carbon 
brushes varv. This has been taken into consideration bv the man- 
ufacturer who has provided a brush especially adapted to his 
machine. 

ELECTRIC MOTOR PRINCIPLES 

Theory of Operation. A machine that is designed to convert 
mechanical into electrical energy or the reverse, is known as a 
dynamo-electric machine. When its armature is rotated by an 
external source of power, such as a steam engine, hydraulic turbine, 
or gasoline engine, it is a generator. By sending a current through 
it from another generator or a battery it converts electrical into 
mechanical energy and is a motor. It is evident, then, that a 
generator and a motor are fundamentally one and the same thing, 
and that by a reversal of the conditions one unit may be made to 


48 


ELECTRICAL EQUIPMENT 


serve both purposes. It will naturally depend upon how closely 
these purposes approach each other so far as their operating con¬ 
ditions are concerned, whether it will be practical to employ the 
same machine for both. In practice, operating conditions rarely 
approximate and so before the advent of the single-unit starting- 
and-lighting system on automobiles the use of the same machine 
for both generating current and converting it into mechanical 
energy was practically unknown. Space considerations were the 
chief factor which led to the development of the single system, 
as the demands on the machine for charging the battery and starting 
the engine are radically different. 

How Rotation Is Produced. The operation of an electric motor 
will be clear if the essentials of a dynamo-electric machine and their 
relations are kept in mind. There is, first, the magnetic field and 
its poles—two or any multiple thereof, though for space reasons 
more than four poles are seldom used in starting motors; then the 
armature, which must also have an even number of poles corre¬ 
sponding to the number of segments in the commutator. Each 
separate coil in the armature winding magnetizes that section of 
the armature core on which it is wound, when the current passes 
through it, as its terminals, connected to different segments on the 
commutator, come under the brushes. In an electric motor having 
either two or four field poles, and eight, twelve, or sixteen armature 
poles, it is apparent that every few degrees in the revolution of 
the armature an oppositely disposed set of its poles is either just 
approaching or just leaving the magnetic field of two of the field 
poles. Bearing in mind that like poles repel one another and that 
unlike poles attract, and that the polarity of both the fields and 
the armature coils is constantly being alternated by the commutator, 
we see that each section of the armature is constantly being attracted 
toward and repelled from the field poles. 

The fundamental law just stated can be easily illustrated by 
taking two common horseshoe magnets, such as can be bought 
for a few cents. Placing their north and south poles together 
it will be found that they have no attraction for each other and 
cannot be made to adhere in this relation. If they had sufficient 
force they would actually move apart when placed on a smooth 
surface in this position. But if one of the magnets is turned around 


ELECTRICAL EQUIPMENT 


49 


so as to bring the north and south poles of the two opposite each 
other, the magnets will be immediately attracted and will hold 
together to the full extent of their force. 

What may be called one cycle of the operation of an electric 
motor may be described as follows: the motor turns clockwise; 
it is of the bipolar type, that is, it has two field poles; and there are 
eight coils on the armature. At the moment assumed, the left 
field pole is the north, and the right south; consequently, the section 
of the armature just entering the field is of opposite polarity, pre¬ 
senting a south pole to the north pole of the field and a north pole 
to the south pole of the latter. The armature is therefore strongly 
attracted. This attraction is maintained by the current in the 
windings continuing in the same direction until the magnetic attrac¬ 
tion reaches a maximum, at which point the stationary and moving 
])oles are practically oppovsite each other. Unless a change occurred 
just at that point the armature would be held stationary and could 
be turned from it only by the expenditure of considerable force, 
that is, assuming that the field did not lose its exciting current. 
(This may be observed on a small scale by attempting to revolve 
the armature of a magneto by turning its shaft by hand.) But 
either at that point, or just before it is reached, the revolution of 
the armature brings a different set of commutator bars under the 
brushes and the direction of the current is reversed in that particular 
winding and with it the polarity of the armature poles. Instead 
of being mutually attracted the armature and field poles become 
mutually repellent. In brief, the armature is first pulled and then 
pushed around in the same direction by reason of the force exerted 
both by the field magnets and by its own magnets. The passing 
of one section of the armature through this change as it enters 
and leaves the zone of influence of a pair of pole pieces may be said 
to constitute a cycle of its operation, by analogy with alternating- 
current generation. The cycles are repeated as many times per 
revolution as there are coils on the armature and the number of 
coils miltiplied by the speed will give the number of changes per 
minute. For example, in a motor assumed to have eight armature 
coils, as in the present instance, there would be, at a speed of 1,000 
r.p.m., 16,000 changes per minute, which makes clear the reason 
for the very smooth pull or torque that an electric motor exerts. 


50 


ELECTRICAL EQUIPMENT 


Counter E.M.F. Though being rotated by means of current 
obtained from an external source of power, it is apparent that the 
motor armature in revolving its coils in the magnetic field is fulfilling 
the conditions previously mentioned as necessary for the generation 
of an e.m.f. Experiment shows that the voltage and current thus 
generated are in an opposite direction to that which is operating 
the motor. It is accordingly termed a counter e.m.f. as it opposes 
the operating current. This, together with the fact that the resist¬ 
ance of copper increases with its temperature and that the armature 
becomes warmer as it runs, explains why the resistance of a motor 
is so much greater when it is running than when standing idle. 
The counter e.m.f. approaches in value that of the line e.m.f., or 
voltage at which current is being supplied to the motor. It can, 
of course, never quite equal the latter for in that case no current 
would flow. The two opposing e.m.f.’s would equalize each other; 
there would be no difference of potential. 

Types of Motors. Being the counterparts of electric generators, 
electric motors differ in type according to their windings in the same 
manner as already explained for generators. The plain series-wound 
motor is nothing more or less than the simple series-wound generator 
to which reference has already been made; the shunt and compound 
motors likewise correspond to the shunt and compound generators. 
But while the series-wound generator was of extremely limited 
application and has long since become obsolete, the series-wound 
motor possesses certain characteristics which make it very generally 
used. It is practically the only type employed for starting service 
on the automobile, and it is also in almost universal use for railway 
service. The reasons for this are its very heavy starting torque 
which increases as the speed of the motor decreases, the quick drop 
in the current required as the motor attains speed, and its liberal 
overload capacity. It is essentially a variable speed motor, and, 
just as the plain series-wound generator delivers a current varying 
with the speed at which it is driven, so the speed of the motor changes 
in proportion to the load. These are characteristics which make 
it valuable for use both as a starting motor for the gasoline engine, 
and for a driving motor on the electric automobile, though in the 
latter case it is seldom a simple series-wound type. As its speed 
is inversely proportional to the load, however, it tends to race when 


ELECTRICAL EQUIPMENT 


51 


the load is light; in other words, it will “run away” if the load is 
suddenly removed, as in declutching from the automobile engine 
after starting the latter, unless the current is instantly shut off or 
very much reduced. This is provided for, as will be explained in 
detail later in connection with the various systems. 

Shunt motors and compound-wound motors are the same as 
their counterparts, the generators of the same types, but as they are 
not used in this connection, no further reference need be made to 
them here. 

Dynamotors. As the term suggests, this is a combination of 
the generator or dynamo and the electric motor, and it is a hybrid 



for which the automobile starting system has been responsible. 
It is frequently mistermed a “motor-generator” and while its assump¬ 
tion of the two roles may justify the name, the use of the term is 
misleading as it becomes confused with the motor-generators 
employed for converting alternating into direct current. The latter 
consist of an a-c. motor on one end of a shaft and a d-c. generator 
on the other end of the same shaft. The two units are distinct 
except for their connection, whereas a dynamotor is a single unit 
comprising both generator and motor, and it can perform only 
one of these functions at one time. A motor-generator, such as is 
used in garages for transforming alternating into direct current 
for charging storage batteries, must carry on both functions at 






























































































































52 


ELECTRICAL EQUIPMENT 



0 2 


-J 

O 

o 


(/> 

o: 

h 

o 

J 

S = 

a> 

Q: Q 


y Z 


53 


O 


23 

O w 

o 

M 


Fig. 35. Windings of Delco Dynamotor 



















































































































































ELECTRIC^AL EQTTIPMENT 53 

the same time in order to operate. That is, the a-c. motor must 
run as a motor in order to drive the d-c. generator and cause it 
to generate a direct current. Hence, the term motor-generator 
as applied to the single-unit type of electric starting system for an 
automobile is not in accordance with the accepted meaning of the 
words and is likely to be confusing. 

A typical example of the dynamotor is to be found in the Delco 
single-unit system, illustrated in Fig. 34. This is really the windings 
of two radically different machines, a shunt-wound generator and 
a series-wound motor, placed on the same armature core and field 
poles. As will be noted, the terminals of the two sets of windings 
on the armature are brought out in different directions and two 

commutators are employed, that at the 
right-hand end being for the generator 
windings, and that at the left for the 
motor. The method of winding the 
armature is illustrated by Fig. 35, which 
shows the generator and motor wind¬ 
ings projected on a plane. In the pre¬ 
ceding illustration the detail at the left 
shows the gearing and starting connec¬ 
tion for coupling the starting motor with 
the flywheel of the engine, the one at 
the right an ignition distributor for the 
high-tension current. Both of these are 
later referred to at greater length. 

Batteries. The only other method known for generating a con¬ 
tinuous, direct current is by means of chemical reactions in what are 
known as primary cells. With the exception of the so-called dry cell, 
a description of these and their workings could be of only historic 
interest and is accordingly omitted here. As no chemical reaction 
could take place in perfectly dry substances this part of the name 
is used simply to distinguish such cells from those using a liquid 
solution. The drv cell iS a zmc-carbon couple. Fig. 36, the zinc 
acting as the container while the carbon is a heavy rod packed in 
manganese dioxide, together with some moisture-absorbing material. 
On the contents of the zinc container as thus filled is poured a 
solution of sal ammoniac and water which forms the active solution 



Fig. 36. Typical Dry Tlattory 














































54 


ELIOC^THK^AL EQUIPMENT 

of the battery. Tlie cell is sealed at the top to })revent evaporation, 
since, when the cell does actually become as drv inside as it is out- 

' *. 4 - 

side it is no longer of any use. Some of its other characteristics are 
mentioned under “Ignition”, Part II. 

"Phe storage battery or accumidator does not generate a current 
in any sense of the word. By means of a much more complicated 
chemical reaction than that of the primary cell it absorbs a charge 
of electricity. Upon the completion of the circuit of a storage 
cell with a suitable load or resistance, such as driving a motor or 
lighting a lamp, a reversal of this chemical process takes place and 
the battery redelivers a part of the current which it has previously 
absorbed. Full details of the characteristics, construction, and 
working of the storage battery are given in the article on “Electric 
Automobiles”. The storage battery and the dry cell are the only 
two forms of battery employed on the automobile so that no mention 
of the other types is necessary, particularly as all but very few of 
them are practically obsolete. 

SUMMARY OF ELECTRICAL PRINCIPLES 
GENERAL PRINCIPLES 

The importance of a knowledge of the fundamental principles 
of electricity and of its characteristics to the man who wishes to 
familiarize himself with the electrical apparatus on the automobile 
to the point where he can readily diagnose and remedy its ills has 
already been dwelt upon. To bring these out more clearly and make 
them easier to memorize, they are repeated here in the form of a 
brief resume in questions and answers. 

Q. What is electrical pressure, and to what may it be com= 
pared? 

A. Electrical pressure is electromotive force, usually termed 
e.m.f., or voltage, also potential, and may be likened to water under 
pressure in a pipe or to compressed air in a container. 

Q. Of what does this electrical pressure consist, and how 
is it measured? 

A. It is represented by the difference of potential between tw.) 
points in a circuit, and it is measured in volts. 

Q. What does the unit volt represent? 


ELE(rnM(14L EQUIPMENT 


55 


A. The volt is the amount of e.in.f. required to force a current 
of one ampere through a resistance of one ohm. 

Q. What is the ampere? 

A. It is the unit of current flow. 

Q. What is the ohm? 

A. The unit of resistance represented by a length of wire 
that will pass one ampere under a pressure of one volt. 

Q. In what unit is the volume of current flow measured? 

A. In the coulomb, which is the equivalent of one ampere 
per second. 

Q. Are the factors of electrical quantity, flow, and pressure 
related, and how? 

A. They are all closely related, and their relation is governed 
bv the factor of resistance. 

ft 

Q. What is resistance, and of what may it consist? 

A. Any element which tends to retard the flow of the current 
is resistance. It may consist of the wire of the circuit itself; the 
windings of different apparatus in the circuit, such as an induction 
coil or a motor; the filament of a lamp; a switch; or the like. 

Q. Are these the only forms that resistance takes? 

A. No. Poor points in wires, dirty and loose connections, 
dirty switch blades, all produce increased resistance in the circuit. 
These are undesirable increases in the resistance. In addition to 
these, there are special resistances intentionally inserted in the 
circuit to serve a definite purpose. These are known as rheostats, 
resistance coils, windings, or grids, according to the form they 
take. 

Q. Why is it desirable to keep the resistance of the circuit, 
outside of that produced by the apparatus itself, at a minimum? 

A. Because any resistance other than that interposed by the 
windings of the motor, the filaments of the lamps, or other useful 
apparatus in the circuit, not only means waste current, but also 
prevents the full amount of current required from reaching the 
desired points. 

Q. How does this waste occur? 

A. In a poor joint, a loose connection, or a dirty switch blade, 
the current is dissipated as heat and accordingly represents that much 
energy passing off into the air. 



ELECTKKJAL EQUIPMENT 


r)() 

Q. Can undesirable resistance be interposed in a circuit in any 
ways other than those already mentioned? 

A. Yes, by the use of wire too small to carry the amount of 
current required by the apparatus. 

Q. What is the effect of using wires too small for the current? 

A. The wires waste a great deal of the current in heat and, if 
much too small for the purpose, are likely to become overheated to 
a point at which they wdll burn the insulation off or to actually become 
fused by the current. 

Q. What determines the voltage in an electrical circuit? 

A. The potential, or voltage, of the source of supply, such as 
a storage battery, in which case the voltage will be constant less the 
drop caused by the resistance of the circuit; or, in the case of a light¬ 
ing generator, it will depend upon the design of the latter (winding, 
etc.) and the speed at which it is running. 

Q. How may the voltage be varied? 

A. In the case of a battery, by varying the number of cells, each 
cell of a storage battery giving approximately 2 volts. In a gen¬ 
erator, by varying the windings of the field and the armature and by 
increasing or decreasing the speed at which it runs. On a circuit 
having a higher voltage than desired, by the insertion of an amount 
of resistance calculated to give the drop required. 

Q. Can lamps of a certain voltage be burned on a circuit having 
a higher voltage? 

A. Not if inserted directly in such a circuit. For example, the 
standard G-volt lamp cannot I)e used directly on a G- or a 12-cell 
storage-battery circuit as employed for tlie lighting and starting 
systems of many cars. The filament would immediately burn out, 
as its thickness is calculated to a nicety to become incandescent when 
current of the voltage for which it is designed is passed through it, 
and anything in excess of this voltage will fuse the wire. 

Q. How can lamps of lower voltage be used on such circuits 
without the employment of a wasteful resistance to cut the voltage 
down? 

A. By cutting down the number of cells employed for the light¬ 
ing, as, for example, where 12 cells are used to operate the start¬ 
ing motor, the battery is divided into four groups of 3 cells each 
for the lighting, these groups delivering current at G volts, while 


VA.VA 'TH 1(^AL PMKN^r 


57 


the complete battery lias a potential of 24 volts. Eliis is termed 
putting the battery into series-multiple connection, which is explained 
further under the head of “Circuits”. 

Q. When the voltage is lower than that required by the lamp, 
what happens? 

A. The lamp filament will give only a dull red glow with a volt¬ 
age drop of but 20 per cent or less of the total, since there is insufficient 
potential to cause the current to bring the filament wire to 
incandescence. 

Q. Is the insertion of any apparatus, such as lamps, a motor, 
etc., in a circuit having a voltage higher than that for which they are 
designed likely to damage them? 

A. Y es, it will burn them out if, for instance, 110-volt lamps 
or motors are connected to 220-volt current, or O-volt lamps put on a 
12-volt circuit. 

Q. Does the opposite also hold true? 

A. No. The apparatus will merely fail to function properly if 
put on a circuit of a voltage lower than that for which it is designed. 

OHM’S LAW 

Q. What is Ohm’s law? 

A. It is the basis of all computations concerning the flow of 
an electric current. It is stated as current equals voltage divided by 
resistance and may be transposed to find any of the three factors, as, 
resistance equals voltage divided by current, so that, given any two of the 
factors, the third may be readily determined. 

Q. How is the power equivalent of an electric current 
expressed? 

A. Power equals current times voltage, the product being 
watts, as one volt times one ampere equals one watt. 

Q. How many watts are there in a horsepower? 

A. 746. Pdectrical horsepower, however, is usually figured in 
kilowatts, or units of one thousand watts, generally abbreviated to KW. 

Q. Given a 6=volt storage battery fully charged and a circuit 
including a starting motor, the total resistance of which (idle) is .1 
ohm, how much current will pass through the motor? 

A. As current equals voltage divided by resistance, we have 
()-^.I =60 amperes. 


58 


la.EC'THK'AL EQUIPMENT 


Q. If, instead of a heavy stranded cable between the battery 
and motor, we substitute a fine wire having a resistance of 10 ohms, 
how much current will pass? 

A. Only .6 ampere. 

Q. What would happen if a very small wire were employed to 
connect the starting motor with the battery? 

A. Not sufficient current would reach the motor to operate it, 
and the wire would probably be fused by the heating effect of the 
heavy current. 

Q. If one horsepower be required to turn the engine over at 
100 r.p.m., and the car is equipped with a 6=volt battery, how many 
amperes will be necessary to start? 

A. As power divided by voltage equals current, 74()-^6 = 124| 
amperes. 

Q. How is the power equivalent usually expressed? 

A. Power equals current times voltage. 

Q. As the voltage is one of the chief determining factors, what 
effect does doubling it have? 

A. Reduces by one-half the amount of current required, exactly 
the same as doubling the pressure of a steam boiler reduces corre¬ 
spondingly the volume of steam necessary to perform the same 
amount of work. 

Q. If the voltage be cut in half, what will be necessary to per= 
form the same amount of work? 

A. The number of amperes, or amount of current, must be 
doubled. 

MAGNETISM 

Q. What is magnetism? 

A. It actually is electricity in another form and is evidenced 
by the attraction or repulsion that one magnet exerts on another, 
or that any piece of magnetized metal has for objects of steel or iron. 

Q. How is this relation between magnetism and electricity 
shown? 

A. By the fact that they are interchangeable. By passing a 
current of electricity through a coil surrounding an iron or steel bar, it 
becomes magnetic; upon moving a magnetized piece of metal close 
to a coil of wire, a current of electricity is induced in the wire. 

Q. What is meant by the polarity of a magnet? 


ELEC’TUICAL EQUIPMENT 


51 ) 


xV. Upon being magnetized, a bar of steel will attract other 
pieces of metal (iron or steel) indiscriminately, but upon being brought 
close to another magnet, it will display an attraction at one end and a 
repulsion at the other for the second magnet. In other words, the 
magnetic attraction at both ends is not the same. These ends are 
termed the poles, one north and the other south, by analogy with the 
compass which is merely a magnetized needle having a natural 
tendency to point north and south. 

Q. What other characteristics do the poles of a magnet display? 

A. They show that the force of the magnet is practically con¬ 
centrated at these poles, as the magnetic attraction is very much less 
at any other part of the bar. 

Q. What is the law of magnetic attraction and repulsion? 

A. Like poles repel one another and unlike poles attract. In 
other words, if a bar magnet be suspended, and the north pole of a 
second magnet be held close to the north pole of the suspended 
magnet, the latter will swing away; if the south pole of the second 
magnet be approached to the north pole of the suspended magnet, 
the latter will swing toward the former until they touch. 

Q. How does the force of this attraction or repulsion vary? 

A. Inversely as the square of the distance, i.e., separating the 
poles by twice the distance reduces the force acting between them 
to one-fourth its value. For example, if two magnets exhibit a 
strong attraction for each other at a distance of one-half inch, the 
attraction will be four times stronger when they are separated by 
only one-fourth inch. 

Q. What are the chief magnetic substances? 

A. Iron and steel. 

Q. What is meant by the magnetic field? 

x\. The space immediately surrounding the i)oles and at which 
the magnetic force is most plainly apparent, as shown by the experi¬ 
ments with filings which graphically illustrate the field of influence 
of the magnet, and from which the term in question originates. 

Q. What is a magnetic circuit? 

A. The path followed by the magnetic flux, or flow, from one 
pole to the other. 

Q. What analogy is there between the poles of a magnet and the 
flow of a current in an electric circuit? 


00 


Kl.KCTlUi^AL E(iUlPMKNO^ 


A. "File current is said to How from the ])ositi\ e, or north, pole 
of a battery or generator, to the negati\'e, or south, pole to complete 
the circuit, exactly as the lines of force in a magnet flow to complete 
the magnetic circuit. 

Q. How can the polarity of a current flowing in a wire be deter= 
mined by a simple experiment? 

A. Hold a small pocket compass close to the wire. If the needle 
of the compass is attracted at its north pole to the wire, the current 
flowing in the latter is negative (south pole), as unlike poles attract, 
and vice verm. This Avill he true only when a direct current is flowing 
in the wire, since an alternating current, as the term indicates, alter¬ 
nates in polarity with every cycle. 

Q. What are lines of force? 

A. The invisible flow of magnetic influence from the north to 
the south pole of a magnet or about any conductor carrying an 
electric current. 

Q. What is a solenoid? 

A. A hollow coil of wire through which a current may be passed 
to produce a magnetic field. 

Q. What is the difference between a permanent magnet and an 
electromagnet? 


A. \Mien a piece of hard steel has been magnetized, either by 
being rubbed on another magnet or by being placed in a solenoid 
th rough which a current is passed, the steel retains a large percentage 
of its magnetism when removed from this magnetic field and is said 
to be a permanent magnet. An electro magnet consists of a soft iron 
or steel C()re on which a coil of wire is wound. When a current passes 
through the wire, the coil becomes strongly magnetic, but when the 


current ceases, the magnetism does likewise. 

Q. When a bar of iron is placed partly in the coil of a solenoid 
through the winding of which a current is passed, what takes place? 

A. The bar is strongly attracted to the center of the coil and 
held there. 

Q. How is this principle taken advantage of in electric starting 
and lighting systems on the automobile? 

A. It is employed for the operation of electromagnetic switches 
for the starting motor, and it is also the principle upon which the 
electromagnetic gear shift depends for its operation. 


KLEC^TKK'AL EQUIPMENT 


()1 


Q. What effect has the insertion of an iron core in a solenoid? 

A. It greatly increases the flow of magnetism through the sole¬ 
noid, with the same amount of current passing through the winding 
of the latter. 

Q. What effect has reversing the direction in which the current 
is passed through the winding of a solenoid? 

A. It reverses the polarity of the latter so that if the core were a 
bar of hard steel, it would be drawn into the opening of the solenoid 
with the current in one direction, and expelled from it when the cur¬ 
rent was reversed. 

Q. What bearing have the principles of magnetic attraction and 
repulsion and of magnetic polarity on electric generator and motor 
operation? 

A. They are the fundamental j)rinciples upon which the opera¬ 
tion of all electric generators and motors are based. 


INDUCTION 


Q. What is the principle of electric induction? 

A. If a circuit carrying an electric current be opened and closed 
(piickly in the case of direct current, and a coil of wire be held close 
to this circuit, a current will be induced in the coil. If the latter be 
wound on an iron core, the induced current will be very much stronger, 
and if both the active circuit and the coil are on the same magnetic 


core, the maximum inductive effect will be produced. The latter is, 
in effect, a transformer, and if an alternating current be sent through 
the first circuit, or coil, there is no need to make and break the circuit 
as where the current is direct. 

Q. Why will a transformer not operate on direct current without 
making and breaking the circuit constantly? 

A. It is necessary to magnetize and demagnetize the core, or, 
where there is no core, to produce a magnetic field and then destroy 
it, in order to produce an inductive effect. 

Q. Why will it operate on alternating current without making 
and breaking the circuit? 

A. Because the alternating current intermittently rises to its 
maximum in one direction, then drops to zero and rises to its maximum 
in the opposite direction, that is, the direction or the polarity of the 
current changes with everv c\'cle. The transformer core is accord- 



ELECTRICAL EC^UIPMENT 


()2 


iiigly magnetized to full strength with a certain polarity, is then 
demagnetized and again remagnetized with the opposite polarity, 
and it is this rise and fall in the strength of the magnetic field from 
zero to maximum, first in one dii;ection and then in the other, that 
causes the inductive effect. 

Q. What is a cycle? 

A. It consists of one alternation from zero to maximum in one 
direction, back to zero and then to the maximum in the opposite 
direction, and back again to zero. The ordinary house-lighting 
supply current is (K) cycles, i.e., it alternates GO times per second, or 
d()()() times per minute. It is owing to this extreme rapidity in alterna¬ 
tion that no flickering is apparent in an incandescent lamp fed by 
alternating current. 

Q. Where alternating current is not available, how can a trans= 
former be operated? 

A. By making and breaking the circuit at a high rate of speed, 
as with a vibrator used on automobile induction coils. 

Q. Why is no vibrator necessary on a coil when fed with current 
from the magneto? 

A. Because the magneto supplies an alternating current. 

Q. On the so=called dual system of ignition, the same coil with¬ 
out any vibrator is used with both the battery and magneto as a source 
of current. How is this effected? 

A. The circuit breaker, or interruptor, of the magneto takes the 
]dace of the vibrator when the’ battery is used for starting, while 
the alternating current from the magneto operates the induction coil, 
or transformer, when the engine is running on the magneto. 

Q. What relation does the induced current bear to the current 
from the source of supply? 

A. This depends upon the transformer and the purpose for 
which it is intended. On the automobile where it is desired to raise 
the current to a high voltage to enable it to bridge the gap of the spark 
plugs, the transformer is known as a step-up type, i.e., it takes current 
at a low voltage and transforms it to one of high voltage, or tension, 
dlie original, or primary, current passes through a winding of a com- 
l)aratively small number of turns of coarse wire on a core of soft iron 
wires. Directly over this winding is a second one consisting of a great 
number of turns of very fine wire. This is known as the sccondarif 


ELECTRICAL ECiUIPMENT 


63 


winding, and the current induced in it is termed a secondary current. 
The voltage of this secondary current depends upon the voltage of the 
source of supply and the proportion that the number of turns in the 
secondary winding bears to that of the primary winding. 

Q. Is the transformer used in any other form or type on tlie 
automobile? 

A. In the so-called true high-tension type of magneto, the trans¬ 
former is made integral with the armature, the fine wire, or secondary 
winding, being placed directly over the coarser winding that serves 
to generate the current. The step-up is the only type of transformer 
used on the automobile. 

CONDUCTORS 


Q. Do materials differ greatly in their ability to conduct elec= 
tricity, and which are the most efficient in this respect? 

A. Thev varv all the wav from absolute insulators to those 

t/ 1 

metals which will ])ass the electric current with the minimum resist¬ 
ance, such as silver, copper, and aluminum. 

Q. Do the characteristics of a material affect its current=con= 
ducting ability? 

A. Very greatly. The harder copper is, the poorer its conduc¬ 
tivity, and this is likewise the case with steel. 

Q. Name the different materials in the order of their current= 
conducting ability. 

A. Silver in pure state, soft copper, brass, aluminum, iron, steel, 
carbon, German silver, etc.; also water, depending upon how alkaline 
or acid it is. 

Q. Is German silver a good conductor? 

A. No. It is known as high-resistance conductor and is accord¬ 
ingly used chiefly for winding resistances and not for the wires of a 
circuit. 


Q. What are some good insulators? 

A. Wood, glass, resin, paraffin wax, silk, cotton, asbestos, rub¬ 
ber, and similar mineral or vegetable substances. 

Q. Are they always equally good imsulators, regardless of their 

condition? 

A. They are efficient as insulators only when dry. The pres¬ 


ence of moisture on any of them aflords a path tor the current to 


cross them. 


04 


ELECTRICAL EQUIPMENT 


Q. What effect on the ability of the conductor to carry a current 
has the amount of material used? 

A. The resistance is increased with a decrease in size and is also 
increased directly as the length of the conductor. 

Q. Where, for mechanical or other reasons, it is not practical 
to use copper or aluminum, how can an equally efficient conductor 
of some other material be provided? 

A. By increasing the amount of material employed in the same 
})roportion that its conductivity hears to that of copper. For 
example, assuming that steel is only one-thirtieth as good a conductor 
as copper, thirty times as much of it must be employed to give the 
same conductivity. 

Q. Give an example of this? 

A. The single-wire system of connecting the starting and light¬ 
ing outfit on an automobile. A small copper cable forms one side of 
the circuit, while the entire chassis forms the other. The ordinary 
trolley-road circuit is another, the small overhead wire forming one 
side of the circuit, and the rails on which the car runs, the other. 

Q. Name some of the materials which are employed for their 
high resistance to the current. 

A. German silver, iron wire, cast iron in the form of grids of 
small cross-section, and carbon. Very fine copper wire is also 
employed wTere the resistance desired is not very great, and space 
considerations permit its employment. 

Q. What is meant by the “specific conductivity” of a material? 

A. Its ability to conduct the current as compared with that of 
pure silver wdiich has a specific conductivity of one. 

Q. Does this ability of a conductor to convey the current vary 
particularly with a great increase in voltage? 

A. Y es. The so-called high-tension current wdiich has been 
stepped-up in a transformer from the b-volt potential of the 3-cell 
storage battery to many thousand volts for ignition purposes will 
cross surfaces and penetrate materials that are perfect insulators to 
the low-tension current. For example, the high-tension current wdll 
leak across a moist wmoden surface or it wdll sometimes puncture the 
one-fourth inch of rubber and cotton insulation of the secondary cable. 

Q. What is one of the chief effects of transforming a current at 
a low' voltage to one of high potential? 


ELECTRICAL EQUIPMENT 


65 


x4. It enables the current to leap an air gap, the width of which 
is proportioned to the voltage itself. The greater the voltage the 
greater the width of the gap it will jump. This is the principle on 
which the spark plug is based. 

HIQH=TENSJON CURRENTS 

Q. When a current of 2 amperes at 6 volts, such as would be 
consumed by the ordinary ignition coil from a storage battery, is 
transformed to a high potential, is the amount of current still the 
same? In other words, can 2 amperes at 6 volts be transformed or 
stepped=up to 2 amperes at 10,000 volts? 

A. No. dhe current decreases as the voltage increases. For 
example, to make the comparison more clear, consider a current of 
10 amperes at 100 volts. This is passed through a step-up trans¬ 
former, of which the ignition coil is a type, and is given a potential of 
1000 volts. The current, however, would then be 1 ampere, that is, 
the current decreases in the same proportion that the voltage is 
increased. The opposite is also true. By passing this current of 1 
ampere at 1000 volts through a step-down transformer, it may be 
converted into a current of 100 amperes at 10 volts. It will be noted 
that the product of volts times amperes in any of the above instances 
cited, or of any possible combinations that can be made, is always the 
same. In other words, a certain amount of energy is sent through the 
transformer, and the same amount, barring losses due to the trans¬ 
formation process itself, is taken out. 

Q. Is there any mechanical analogue of this process of trans= 
forming a current up or down to impress upon it a greater or lesser 
potential? 

A. There is nothing in mechanics that corresponds exactly to 
this peculiar property of electricity. The resulting change in the 
form in which the energy is applicable as a result, however, may 
readily be compared with mechanical standards. For example, 
we may have in a very small boiler, a pressure of 1000 pounds to the 
square inch, but a volume of only one cubic foot of steam. This 
small amount at its high pressure represents the equivalent in energy 
of 10 cubic feet of steam at a pressure of 100 pounds. 

Q. What is the object of stepping the current up to such high 
voltages? 


66 


ELECTRICAL EQUIPMENT 


A. On the automobile, simply to enable it to jump the gap of 
the spark plug and fire the charge. In ordinary commercial service, 
to permit of sending it long distances with a minimum expenditure 
for copper wire and a minimum loss in the amount of energy 
transmitted. 

CIRCUITS 

Q. What is meant by an electric circuit? 

A. The path by which the electrical energy, or current, is said 
to flow from and return to its source. 

Q. Is a circuit absolutely necessary in order to permit of utiliz= 

ing electricity? 

A. Unless there is a circuit or complete path for the current, 
it does not flow. 

Q. Must a circuit be comprised completely of wires leading 
from, and returning to, the source, such as the battery or 
generator? 

A. No, it is not necessary that wire be used for both sides of 
the circuit. One side or the other may be composed of a ground, 
such as the tracks of a trolley system, the overhead wire consti¬ 
tuting the other side of the circuit, or in the case of a single-wire 
lighting and starting system in which one cable is employed to con¬ 
duct the current from the battery to the starting motor and lights, 
and the chassis itself forms the ground return for both. 

Q. How many forms of circuits are there in general use? 

A. Three: the series, the multiple, and the series-multiple. 
In the first, all apparatus in the circuit is in series. That is, all the 
current from the source must pass through each instrument or light 
in turn to complete the circuit. In the multiple type of circuit, 
every instrument or light on it is independent of all the others. 
Lights may be turned on or off, motors started or stopped, without 
interfering in any way with any of the others. As its name indicates, 
the series-multiple is a combination of the two forms of circuits. For 
example, in using incandescent lamps to cut down the current for 
charging a storage battery from the lighting mains, the lamps them¬ 
selves are in multiple, but the whole bank of lamps is in series with 
the storage battery. See illustration on charging storage battery 
direct from lighting mains. 


ELECTRICAL EQUIPMENT 


07 


Q. Which of these forms of circuit is in most general use on the 
automobile? 

A. All three will be found on practically every car equipped 
with a starting and a lighting system. For instance, the starting 
motor is operated in series with the battery, while the lamps are wired 
in multiple for the side and head lights, and the speedometer and tail 
light are wired in series as a branch of the multiple-lighting circuit, 
thus giving a series-multiple circuit. The ignition distributor, coil, 
and battery are in series. 

Q. What is meant by a grounded circuit? 

A. This is ordinarily used to indicate that through lack of 
insulation at some part of the wire, or similar injury, the circuit has 
been shortened, owing to this bare wire touching a ground, thus per¬ 
mitting the current to return to its source without passing through 
whatever instruments there may be on the circuit. A grounded cir¬ 
cuit, however, is also one in which one side consists of a ground return 
instead of having two wires. This is frequently distinguished by 
being termed a ground-return circuit. 

Q. What is a short=circuit? 

A. As the term indicates, a completion of the circuit short of the 
point or apparatus which the current is intended to reach. The 
example just cited is a short circuit as well as a ground, sometimes 
termed a grounded short-circuit. In other words, the abrasion of the 
insulation of one of the conductors has permitted the current to 
escape by a convenient path of return which, being of less resistance 
than the one it is intended to take, prevents any current from reaching 
the apparatus in the circuit. A ground is practically always a short- 
circuit, but the reverse is not always true, that is, a short-circuit need 
not necessarily be a ground, as in a double-wire circuit, but the two 
conductors may come together at a point where the insulation is 
worn, or winding of a coil may break down and cause a short- 
circuit. 

Q. What are some typical examples of grounded circuits on the 
automobile? 

A. Both the primary and secondary sides of the ignition circuit 
and the starting and lighting circuits of the so-called single-wire sys¬ 
tems in which the chassis is always used as a ground return for all the 
circuits employed. 


68 


ELECTRICAL EQUIPMENT 


HYDRAULIC ANALOGUE 

Q. What is a hydraulic analogue, and what bearing has it on an 
electrical system? 

A. It is a comparison of the electrical system with a hydraulic 
or water-pressure system and serves to make clear the resemblance 
or analogy that exists between the principles upon which both operate. 

Q. What type of hydraulic system is similar to an electrical 
system consisting of a generator, external circuits, and lamps, motors, 
or the like, as a load? 

A. A constant-pressure system in which the pumps keep the 
water in the pipes under a certain amount of pressure corresponding 
to the demand. When the demand increases, the supply does like¬ 
wise and vice versa. (In the case of the pumping system, this is not 
automatic, but is controlled by the attendant.) 

Q. To what does the pressure of such a pumping system corre= 
spond in the electrical system? 

A. ‘To the voltage, or electromotive, force. 

Q. Can there be voltage, or potential, in an electrical system 
without a flow of current? 

A. Yes, exactly as in the pumping system in which there is 
always a constant pressure on the water in the pipes whether the 
water is escaping through any of the outlets or not. In other words, 
there may be pressure but no flow. The same thing is true of the 
generator. If it be turning at its normal speed and is wound to 
produce current at 100 volts, there will be a potential of 100 volts 
across its terminals, even though there are no lamps or motors 
switched on in the external circuit. 

Q. How does the resistance of the pipe lines in the water system 
compare with the resistance of the wires in a circuit to the electric 
current? 

A. It is nearly the same. It varies inversely as the size of 
the pipe and directly as its length. The smaller the pipe the greater 
the resistance per foot; the longer the pipe the greater the total 
resistance. In the same way, the resistance to the electric current 
increases with the decrease in the size of the wire and increases with 
the length of the wire, the chief difference being that bends or turns 
ill the wire do not add to the electrical resistance, whereas bends in 
the pipe impose greatly added resistance to the flow of water. 


ELECTRICAL EQUIPMENT 


69 


Q. What comparison may be made between the speed at which 
the generator and the pumps run? 

A. The greater the speed, the greater the pressure in the case of 
the pumps, and of the voltage in the case of the generator. Below 
ii certain speed, usually termed the normal speed, there is a sharp 
falling off in the pressure in both. Neither can be operated safely 
at an excessive speed. 

Q. What is the cause of the increase in voltage with increasing 
speed in the case of the generator? 

A. A oltage, or electromotive force, is generated by the coils, 
or windings, of the armature cutting the magnetic lines of force of 
the field of the generator. The greater the number of times that 
these coils pass through the lines of force per minute, the greater 
the voltage will be. 

Q. How does fall in pressure correspond to voltage drop? 

A. To reach the end of the piping system, the water must over¬ 
come the resistance of the latter to its passage, and the friction 
involved robs it of some of its pressure in overcoming this resistance. 
Uonsequently, there is less pressure at the outlet a mile away from 
the pumps than there is at the pumps themselves. The same thing is 
true of the electric circuit. The current must force its way through 
the wires by reason of its voltage or pressure and, in so doing, some of 
the voltage is lost in overcoming the resistance of the wires, joints, 
switches, and the like. In both cases allowance for this loss is made 
by increasing the pressure at the source by an amount equivalent to 
the loss in transmission. For example, in electric street-railway work 
the motors are wound to operate on current at 500 volts, while the 
generators in the powerhouse produce current at 550 to 600 volts, 
the difference being known as the voltage drop. 

Q. Is this an important matter on the automobile where the 
circuits are so short? 

A. It is of considerable importance, particularly in connection 
with the starting motor circuit. The circuits are very short, but the 
initial voltage is likewise very low, so that the percentage available 
for voltage drop is correspondingly limited. For example, a drop of 
one volt in a 110- to 115-volt lighting circuit is negligible, being less 
than 1 per cent, but a drop of one volt in a 6-volt circuit represents 
almost 17 per cent and would accordingly be prohibitive. As poor 


70 


ELECTRICAL EQUIPMENT 


connections, dirty switch contacts, dirty commutator, and worn 
brushes are apt to increase the resistance to a point where the voltage 
drop is in excess of this, the importance of properly maintaining these 
parts of the system may be appreciated. 

Q. How does the flow of water correspond to the flow of 
current? 

A. In both cases, the amount is proportionate to the resistance 
of the outlet and to the pressure back of the current, whether water 
or electricity. In other words, the volume of water that will flow 
depends upon the size of the outlet (the smaller the outlet the greater 
the resistance to the flow) times the pressure back of it. In the same 
way the number of amperes that will flow when the circuit is closed 
depends upon the voltage of the circuit divided by the resistance 
(Ohm’s law). For example, the ordinary 10 c.p. carbon-filament 
lamp for a 110-volt circuit has a resistance of 220 ohms, which, 
divided by 110, gives J ampere as the current that will flow when the 
lamp is switched into the circuit. 

Q. Can the piping system properly be compared with an electric 
circuit? 

A. In practically every way except that of the return required 
for the latter. For example, the opening of a series of outlets in the 
piping system reduces the pressure in proportion to the number 
opened; so in connecting a number of different pieces of apparatus 
in series in an electric circuit, the voltage through each will decrease 
as another is added. It may also be compared with a parallel or 
multiple circuit in that the opening of one outlet does not prevent 
drawing water from another. A break in a main corresponds to a 
short-circuit or a ground in that no water can then be drawn from any 
outlet beyond the break. The- comparisons between the piping 
system and the circuit are not exact, owing to the lack of any neces¬ 
sity for a return in the case of the water piping, but they serve to 
make clearer some of the fundamentals of the electric circuit. 

GENERATOR PRINCIPLES 

Q. What makes it possible to generate a current of electricity 
by mechanical means? 

A. The fact that electricity and magnetism are different m_ani- 
festations of the same force and that, given one, the other may be 


ELECTRICAL EQUIPMENT 


71 


produced. Also the fact that they are readily interchangeable, 
i.e., one may be readily converted into the other. 

Q. On what fundamental principle does the generation of elec= 
tricity in this manner depend? 

A. That of induction. 

Q. How is it utilized? 

A. By revolving a coil of wire in the field of a magnet. 

Q. What occurs when this is done? 

A. An e.m.f. is generated in the coil. 

Q. Describe the simplest form of generator. 

A. Such a generator consists of a horseshoe magnet between 
the poles of which a coil of wire is revolved. 

Q. What governs the strength of the e.m.f. or potential, thus 
generated? 

A. The speed with which the conductor or wire revolves, or is 
said to “cut the lines of force” of the magnetic field. 

Q. How can this potential be further increased? 

A. By winding the coil of wire on an iron core, as the iron 
becomes strongly magnetic and greatly increases the inductive effect. 

Q. What is this simplest form of generator consisting of horse= 
shoe magnets for the field and of a single winding on an iron core 
termed, and for what is it employed on the automobile? 

A. It is known as a magneto and is generally employed for pro¬ 
ducing the current needed for ignition purposes. 

Q. Can such a generator be directly employed for charging a 
storage battery or for lighting lamps? 

A. No, it cannot be used for charging purposes, since it gen¬ 
erates an alternating current. Moreover, owing to the small number 
of poles (two), its single winding, and the high speed at which it is 
driven, it produces very little current but a high e.m.f., as this is 
desirable for ignition. It cannot be used for lighting purposes for 
the same reason, i.e., the simple winding produces an alternating 
current with a very perceptible interval between the alternations, or 
cycles, so that a lamp would flicker very badly. As its e.m.f., or 
voltage, is proportionate to its speed and as there is no method of 
controlling it, the lamp would be burned out as soon as the magneto 
was speeded up. 

Q. What are the essentials of this simple form of generator? 


72 


ELECTRICAL EQUIPMENT 


A. The field consisting of the horseshoe magnets, and the arma¬ 
ture consisting of a soft iron or steel core, usually in the form of an H, 
in the slots of which, the single winding of comparatively coarse wire 
is wound. 

Q. Why is the field of a magneto usually referred to as a 
manent field?” 

A. Because it consists of so-called permanent magnets. Nat¬ 
urally, they are not permanent in the real sense of the word, but their 
magnetism is constant while it lasts and it decreases only very grad- 
uallv under the influence of heat and vibration. 

4 / 

Q. Why does heat affect the magnetism of the field of a genera= 
tor of this type? 

A. Because a piece of hard steel that is strongly magnetic when 
cold loses its magnetism altogether when raised to a sufficiently high 
temperature. In other words, if heated to a bright red and then 
cooled, it is no longer a magnet, and the steel must be remagnetized. 
Constant vibration has the same effect, but it is much slower. 

Q. Is there any other way of increasing the voltage of such a 
generator besides running its armature at a higher speed? 

A. Yes, by increasing the number of turns of wire in the wind¬ 
ing, which has the same effect as revolving a single coil at a higher 
speed. 

Q. How is the current produced by a simple form of generator, 
such as the magneto, conducted to an outside circuit? 

A. Ordinarily, this would be done by means of slip rings, i.e., 
plain bands of copper mounted on the armature shaft with narrow 
copper brushes bearing on these rings, as is the case with large alter¬ 
nating-current generators. But as the ignition system of the auto¬ 
mobile is a grounded circuit, one end of the armature winding of the 
magneto is connected directly to the core of the armature, and the 
other is led to a small V-shaped ring or to an insulated stud on the end 
of the shaft against which either a copper or a carbon brush is held 
by a small spring. 

Q. What is the cause of the alternating cycle of the magneto, 
and at what points in the revolution of the armature does it occur? 

A. In revolving in the field of the magnets, the armature passes 
successively from the field of influence of a north pole to one of 
opposite polarity, so that the direction of the e.m.f. is reversed. 


ELECTRICAL EQUIPMENT 


73 


When the armature is in a horizontal position in the field, the e.ni.f. 
curve is at zero; as it turns, the edges of the armature core pass the 
ends of the pole pieces of the field, and the e.m.f. rises sharply to a 
maximum as the central line of the core passes the ends of the poles, 
when it is said to be cutting the maximum number of lines of force. 
It drops off again quickly from this point and again reaches zero, 
when the armature is in a vertical position. As its ends come under 
the influence of opposite poles, the curve again rises, but is now in the 
opposite direction, or of opposite polarity. In other words, it passes 
from zero to maximum and back again in every half revolution, or 
180 degrees. 


Q. How can a generator be made to produce a direct, instead of 
an alternating current? 

A. The current is always alternating as generated in the arma¬ 
ture, but it may be conducted to the outside circuit as a unidirec¬ 
tional, or so-called direct, current by the addition of a commutator. 

Q. Can such a current be produced by the addition of a commu= 
tator to the simple single=coil winding already mentioned in connec= 
tion with the magneto? 

A. Y es, but as the commutator woidd have but two parts, the 
e.m.f., while passing in one direction, would be strongly pulsating. 

Q. What is a commutator and how does it convert the alternat= 
ing current produced in the armature to a direct current in the outside 
circuit? 

A. It consists of a number of segments of copper, one for each 
coil terminal of the armature, i.e., two for each complete coil of the 
winding. These segments are insulated from one another, and 
brushes bear at opposite points of the conducting hub thus formed by 
the segments. As the terminals of the armature coils are connected 
to segments that are opposite one another (in the simplest forms of 
winding), and as the brushes, also opposite one another, are set at 
points so that they pass from one segment to another when the rate 
of cutting is at a minimum in the armature winding, their relation to 
the latter is changed each half revolution. In other words, at the 
point in the revolution where the polarity of the e.m.f. generated 
reverses, the relation of the brushes to the winding is also reversed, 
so that the direction of the e.m.f. is accordingly always the same. See 


Figs. 20 and 21. 


74 


ELECTRICAL EQUIPMENT 


Q. How is the pulsating nature of the direct current thus gener= 
ated overcome? 

A. By adding coils and commutator bars to the armature so 
that new coils come into action before the e.m.f. produced in those 
just preceding them under the brushes has an opportunity to drop 
much below the peak or maximum. Thus, only the peak of the 
wave is utilized, and the e.m.f. of a direct current consists of a series 
of these wave peaks overlapping one another. 

Q. Are permanent magnets used for the fields of all generators? 

A. No, only for those of magnetos. In other types, an electro¬ 
magnetic field is used. 

Q. What are the advantages of the permanent field for use in 
connection with the magneto? 

A. It is always at its maximum strength, so that the magneto 
generates a powerful e.m.f., even though turned over very slowly. 
Regardless of the speed of the armature, the strength of the field 
remains the same, so that no controlling devices are necessary to 
prevent the armature from burning out, owing to excessive speed. 

Q. What is an electromagnetic field and how is it produced? 

A. It is based on the fact that when a current of electricity is 
sent through a winding surrounding an iron core, the core becomes 
strongly magnetic. It accordingly consists of windings on the fields 
of the generator, in addition to those on the armature. Depending 
upon the particular type of generator in question, either all or only 
part of the current produced in the armature is sent through the 
windings of the field. The latter is then said to be self-excited in that 
it depends upon no outside source. 

Q. Is the self=excited field characteristic of all generators 
except the magneto? 

A. Yes, of all direct-current generators. Large alternating- 
current generators are said to be separately excited, a smaller direct- 
current generator being employed solely for the purpose of rendering 
the fields of the larger machine magnetic. 

Q. What is a series=wound generator, and why is this type not 
used on the automobile? 

A. It is one in which the entire current generated in the arma¬ 
ture is passed through the field windings. It does not generate until 
a high speed is reached. Its voltage varies sharply as its speed, and 


1 


ELECTRICAL EQUIPMENT 


/O 


I it may have its polarity reversed by the battery if its speed drops 
j below a certain point, consequently, it is not fitted for charging 
I storage batteries. (In fact, the series-wound generator is practically 
i obsolete, except for some special uses.) 

Q. What are shunt= and compound=wound generators? 

A. In the former, the windings of the armature and of the fields 
are in multiple, or shunt, so that only a certain amount of current, 
depending upon the difference in the resistance of the outside circuit 
and that of the fields, passes through the windings of the latter. As 
the load and consequently the resistance of the outside circuit 
increases, more current passes through the shunt, and the fields 
become more strongly magnetic, thus increasing the output so that 
the generator is, to a certain extent, self-regulating. 

In the compound type, there is, in addition to the main shunt 
winding on the fields, an auxiliary winding of heavier wire (lower 
resistance) which is connected in series with the armature. As in a 
series-wound generator, the amount of current exciting the fields is 
directly proportional to the speed, more current in proportion passes 
through the compound winding than through the shunt winding as 
the load is increased, and the generator is self-regulating to a much 
greater degree. The compound-wound type of generator is in prac¬ 
tically universal use on the automobile as well as for general power 
purposes. See Figs. 31 and 32. 

Q. What is meant by the term “self=regulating” as used in the 
preceding paragraphs? 

A. The generator automatically produces more current in 
response to the demand occasioned by an increase in the load, without 
any change in its driving speed. 

Q. How is this accomplished? 

A. The amount of current produced by the generator depends 
upon the strength of its magnetic field in which the armature revolves. 
The magnetism of this field represents the so-called lines of force. 
The greater the number of lines, or the more powerful they are per 
unit of pole-piece surface, the greater the volume of current that will 
be generated. In practical usage, this is referred to as the magnetic 
flux, or flow, through the armature. By increasing or decreasing 
the amount of this magnetic flux through the armature, the current 
output can be controlled within close limits. 


76 


ELECTRICAL EQUIPMENT 


Q. What is meant by the “load” on a generator? 

A. The lamps, motors, storage battery, or similar apparatus to 
which it is supplying current. 

Q. As the speed of the generator itself does not increase, how 
does it provide for an increase in the load? _ 

A. By absorbing more power from its driving unit. For 
example, if a generator be operating with only ten lOO-watt lamps in 
the circuit, it is requiring approximately one and one-half horsepower 
to drive it. Now, if another group of ten lamps of the same size be 
switched on, the amount of power demanded by the generator of its 
engine will be doubled. This may be very readily demonstrated in a 
rough way by fitting a handcrank to any small automobile generator 
and turning the machine over with one lamp in the outside circuit. 
It will be found very easy to spin the generator very rapidly by hand, 
as practically no resistance is felt. Now connect in the circuit a 
discharged storage battery, and the additional power required to 
turn the machine will at once be very perceptible. 

Q. What are the brushes and what purpose do they serve? 

A. They are strips of copper or carbon (the latter is now almost 
universally used), which serve to conduct the current generated in 
the armature to the outside circuit and to the field windings by 
bearing on the revolving commutator. Except where an additional 
brush is employed for regulating purposes, there is usually one brush 
for each pole of the field, i.e., a bipolar generator is fitted with two 
brushes, a four-pole with four brushes. The brushes are held against 
the commutator by springs. Soft copper embedded in carbon is also 
em])loyed, especially for low-voltage generators, such as the lighting 
generator on the automobile. 

ELECTRIC MOTORS 

Q. Is there any difference in principle between the electric 
generator and the electric motor? 

A. Fundamentally, they are the same, as is evidenced by the 
fact that either is reversible, that is, an electric generator, when 
supplied with current from an outside source (of the proper voltage, 
of course), will operate as a motor, and a motor, when driven by an 
outside source of power, will generate an electric current. They are 
naturally not interchangeable in practice, owing to differences in 


ELECTRICAL EQUIPMENT 


77 


design and winding. The generator is wound to produce the maxi¬ 
mum amount of current at a certain voltage with a given horsepower, 
while the motor is designed to produce the maximum amount of power 
with the minimum current. 

Q. What is the operative principle of the electric motor? 

A. That of magnetic attraction and repulsion. 

Q. How is it applied? 

A. As in the generator, both the fields and the armature of the 
motor consist of electromagnets. The brushes and the commutator 
serve the same purpose of reversing the direction of the current 
through the armature coils every time a different pair of commutator 
segments passes under the former. As has already been explained, 
reversing the direction of current flow through the winding of an 
electromagnet reverses the polarity of the magnet itself. To siin- 
})lify the illustration, take a bipolar motor with a two-pole armature 
having but a single winding. When the current is switched on, the 
armature is at a 45-degree angle, so that its poles are just under the 
poles of the field. As the commutator causes the current to flow 
through the armature winding in a reverse direction to that of the fields, 
unlike poles will be created. They will attract each other, and the 
armature will revolve a small part of a revolution, until it is directly 
in the strongest part of the field of the influence of the field magnets. 
Just as this point is reached, however, the brushes pass on to new 
segments of the commutator, and the direction of the current in the 
armature coils is instantly reversed. The polarity of the armature 
core is also reversed, so that there are now like poles opposed to one 
another, and they repel, causing the armature to complete another 
part of its revolution, when the former conditions are again estab¬ 
lished and the armature is again attracted. In a bipolar motor with 
a simple two-pole armature, there would be two phases of attraction 
and repulsion per revolution. In larger motors this is multiplied by 
the number of poles in the field and the number of coils on the 
armature. 

Q. As an electric motor in running fulfills all the conditions 
necessary for the generation of an e.m.f., what becomes of this 
voltage? 

A. It constitutes what is termed a counter e.m.f. and serves the 
useful purpose of increasing the resistance of the motor when in 


78 


ELECTRICAL EQUIPMENT 


operation, thus reducing the amount of current necessary to drive it. 
For example, when the motor is standing idle, the resistance of its 
windings is low. It is for this reason that large direct-current motors 
(one h.p. or over) cannot be started without the aid of an outside 
resistance to cut down the starting current, otherwise the armature 
would be burned out. As the armature speeds up, the counter e.m.f. 
generated opposes that of the driving current and accordingly 
increases the resistance. The heating of the windings in operation 
further serves to increase the resistance, as the resistance of most 
metals increases with a rise in their temperature. 

Q. How many types of motors are there, and what type is most 
generally used for automobile starting? 

A. As they correspond exactly to generators, there are the 
same number of types, i.e., series, shunt, and compound wound. 
The series type is almost universally employed on the automobile and 
is also very largely used on trolley cars. 

Q. If the series=wound generator is of so little practical applica= 
tion, how is it that the series=wound motor is found so advantageous? 

A. The same characteristics that are a disadvantage in the 
generator are correspondingly valuable in a motor, which explains 
why generators and motors are not interchangeable in practice, as 
already mentioned. x4 series-wound machine is essentially a variable- 
speed machine, and this is not desirable in a generator, while it is in a 
motor. The series type of motor has a very heavy starting torque, 
or pull, which increases as the speed of the motor decreases. This is 
exactly what is wanted to overcome the inertia of the gasoline engine. 
Its current consumption falls off very quickly as its speed increases, 
and it has a very liberal overload capacity, being capable of carrying 
loads up to five times the normal, for short periods. 

Q. As the speed of the series motor decreases in proportion to 
the load, what happens when the load is suddenly relieved as in the 
starting of the gasoline motor? 

A. The electric motor tends to race, or run away. 

Q. How is this prevented on the automobile? 

A. The method employed differs in different systems, but, as a 
rule, the starting of the gasoline engine automatically opens the 
starting motor circuit, or means are provided for greatly reducing the 
amount of current it receives the moment the load.is removed. 


ELECTRICAL EQUIPMENT 


79 


Q. Are either shunt= or compound=wound motors used on 
automobiles? 

A. They are employed on electric vehicles, but not in connec¬ 
tion with the starting systems used on gasoline cars. 

Q. What is a motor=generator, and what is it employed for? 

A. As its name indicates, it consists of two units, a motor and a 
generator, the former having an alternating current, and the latter a 
direct current. It is employed for converting an alternating current 
into a direct current, so that it may be utilized for charging storage 
batteries. The alternating-current supply is used simply for running 
a motor of that type to Avhich is directly coupled a direct-current 
generator. There is no electrical connection between the two 
machines. 

Q. Are motor=generators ever used on automobiles? 

A. No, but the combination of a direct-current generator and a 
starting motor in one machine, as in the single-unit systems, is fre¬ 
quently so-called through error. This single unit is variously termed 
a dynamotor and a genemotor to distinguish it from a motor-generator. 

Q. How are the two radically different purposes for which the 
generator and the motor must be designed combined in one machine? 

A. By putting independent windings on the fields and the arma¬ 
ture, and, in some instances, by employing two commutators at 
different ends of the armature shaft. 

BATTERIES 

Q. What other method is there of producing an electric current 
besides that of driving a dynamo? 

A. The use of batteries known as primary and secondary cells. 

Q. What is the difference between these two types? 

A. In the primary cell, the current is generated by means of 
the chemical reaction taking place between electrodes of different 
materials in an acid or alkaline solution, one electrode being dissolved 
in the solution as the chemical action continues. 

The secondary cell is the storage battery. This does not generate 
a current of electricity as in the case of the primary cell, nor does it 
actually store electricity as its name would indicate. The passing of a 
current through its elements brings about a chemical conversion of the 
latter, which is reversed when the current flows out of the cell. 





DELCO DISTRIBUTOR FOR PACKARD “TWELVE” ENGINE 

Courtesy of Dayton Engineering Laboratories Company, Dayton, Ohio 






ELECTRICAL EQUIPMENT FOR 
GASOLINE CARS 

PART II 


IGNITION 

FUNDAMENTAL IGNITION PRINCIPLES 

Faulty Ignition Cause of Much Early Trouble. IMore than 
half of the troubles encountered by the designers and the drivers 
of the early automobiles were the direct results of the extremely 
crude ignition systems at first adopted. With knowledge of gaso¬ 
line-motor operation generally scant at that time, much of this 
trouble was attributed to causes entirely foreign to its real source 
or, on general principles, the motor was roundly “cussed” as a 
deep and unfathomable mystery. Subsequently it became plain 
that much of this inexplicable tendency to balk was due to the 
elusiveness of the electric current. Crude insulation and contacts, 
inherently defective spark plugs, and extremely wasteful current¬ 
handling devices, fed from a weak source, were the causes. 

Distinctions between Low Tension and High Tension. A 
low-tension ignition system uses a low-tension current—i.e., the 

output of a battery or 
small generator, em¬ 
ployed at the voltage at 
which it was produced, 
or, in other words, a 
primary current. A 
high-tension uses a 
high-voltage current 
produced by passing 
the output of the 
battery or other source 
of supply through 
a step-up transformer (induction coil). As this is taken from 
the secondary winding of the coil, it is sometimes referred 



Fig. 37. Voltage Required to Force a Spark Across a 
.020-Inch Gap Under Different Compression Pressures 


























82 


ELECTRICAL EQUIPMENT 


to as a secondary current. It is the result of induction and is com¬ 
monly termed a high-tension current owing to its great voltage or 
potential. The battery produced current of high amperage value 
at 6 to 8 volts, which after being passed through the coil became a 
current of microscopic amperage value at anywhere from 10,000 to 
25,000 volts, according to what the designer of the coil thought was 
sufficient potential to produce a good spark, that is, to enable it to 
readily jump the gap in the points of the plug. The curve. Fig. 37, 
shows the voltage necessary to force a spark across a given distance 
in air under various pressures. 

As the low-tension current will not jump an air gap, a further 
distinction between the two systems is the employment of totally 



Fig. 38. Diagram of Low-Tension Ignition System 


different types of spark plugs. In the former, a mechanically 
operated plug, i.e., one that is held closed until the maximum current 
is passing through it and is then suddenly opened by being mechan¬ 
ically tripped by a cam or rod operated by the engine, is essential. 
Such a plug produces a spark that is immensely superior in heating 
value and, consequently, in igniting ability, to the usual thin spark 
that bridges the gap of a high-tension spark plug. But this most 
desirable quality is likewise quickly destructive of the contact 
points, necessitating frequent readjustment of the mechanically 
operated plugs. Moreover, the mechanical lag or time element of 
operation, due to the inertia of the numerous moving parts, rendered 
it difficult to make a low-tension spark plug suitable for a high- 
























































ELECTRICAL EQUIPMENT 


83 





m»8= 



speed engine without resorting to the most expensive machine work, 
and much greater skill was necessary for their proper adjustment. 
The shortcomings of the original high-tension systems were so 

glaring, however, that some of 
the most successful automo¬ 
biles of earlier days were fitted 
with low-tension ignition. 

Low=Tensioii System. 
Pig. 38 shows diagrammatically 
the essentials of a low-tension 
system for a single-cylinder 
motor, while Pig. 39 shows a 
complete low-tension system 
for a four-cylinder motor. The 
details of the operating mech¬ 
anism and the plug are shown 
in Pigs. 40 and 41. Referring 
to Pig. 38, A is the battery 
(a magneto, dynamo, or any 
other suitable source of cur¬ 
rent may be used), R is a 
spark coil, and C, Z), and E 
are the elements of a make- 
and-break device that is me¬ 
chanically actuated at regular 

intervals bv the motor itself 

1/ 

to produce the sparks within 
the cylinder. As shown in the 
drawing, the circuit is com¬ 
pleted by grounding the wires 
from one side of the battery 
on the cylinder base, or any 
other portion of the machine, 
as at F, In this figure D is a 
small insulated plug entering 
the interior of the cylinder, usually through one of the valve 
caps, while C is a movable arm (see also Pig. 40), that makes 
and breaks contact with R, at the point R, when it is given a 





CO 

.... 

CO 

K 

o 


B 

4 ) 

..J 

CO 

>> 

CZi 

o 


fl 

M 


a 

.2 

'(O 

a 

<u 

I 

cs 

o 

Ch 

OJ 

.S 

O 

I 

tl 

3 

o 


o> 

CO 

bi) 
* ^ 

fa 

























































84 


ELECTRICAL EQUIPMENT 


slight rocking movement. For the 
best results this rocking movement 
must be very sharp and rapid, in the 
nature of a snap, and it must, of 
course, be correctly timed to occur 
in proper relation to the moment 
when the spark is required. (See 
also Fig. 41.) 

The chief advantage of low- 
tension ignition is its immunity from 
troubles caused by short-circuiting by 
leakage of the current through poor 
insulation or across moistened termi¬ 
nals. This led to its almost universal 
employment on motor boats for a 
number of years, but it has since 
been generally abandoned even for 
marine use so that it is now only to 
be found on stationary engines, the 
low rotative speeds of which make 
it practical. So far as the automo¬ 
bile is concerned, the low-tension 
system is only of historical inter¬ 
est as it is already several years since 
it was wholly discarded. 

High=Tension System. High- 
tension ignition systems are based on 
the fact that when a sufficiently high 
potential is impressed upon a current 
of electricity, it will leap an air gap or 
other break in the circuit of a width 
dependent upon the potential or volt¬ 
age itself. In bridging such a gap, 
the current becomes visible in the 
form of an arc, flash, or spark, depend¬ 
ing upon its duration and intensity, 
and it will readily ignite a gasoline 
or other gaseous fuel mixture. Its 




Fig. 41. Low-Tension Spark Plug 
{Horseless Ape) 


r-r 















































ELECTRICAL EQUIPMENT 


85 


very ability to do so, however, was one of the most prolific sources of 
trouble in the early days, as the designer’s conception of the insulation 
required to conduct such a current without grounding or short- 
circuiting was far from approaching the reality. 

The essentials of a high-tension system are shown diagram- 
matically in Fig. 42. A is the source of current, usually a battery in 
earlier days, as indicated by the conventional sign, placed in a 
primary circuit that also includes the contact maker C, the primary 
winding of the coil B, and the vibrator G. The contact maker C is 
positively driven by a connection with some revolving part of the 
motor, so that it makes contact at the exact time ignition is required 
in each cylinder. 



With a system of the type described, when contact is made the 
first result is attraction of the vibrator blade E by the magnetized 
core II of the coil. This, by drawing E away from the contact screw 
G, at once breaks the primary circuit again, and this demagnetizes 
//, with the result that E again springs into contact with G. The 
effect of this is to cause a rapid series of current surges through the 
coil B, as long as the contact maker C maintains the contact. 

Each time a surge of primary current passes through a coil, a 
secondary current of very high voltage is induced in the secondary 
circuit, which is grounded on the cylinder at F and connected at B 
with the spark plug. This plug, for high-tension ignition, has an 
open gap of about ^ inch at I, across the resistance of which gap the 
current will jump, because of its high tension. Ignition is thus 
effected by a rapid succession of sparks across /. 














































86 


ELECTRICAL EQUIPMENT 


This briefly describes what may be termed the rudiments of a 
high-tension ignition system and the diagram shows their relation to 
one another. Of course, this simply has reference to a single-cylin¬ 
der motor. For each extra cylinder in an ignition system of the type 
illustrated, there is another contact point on the timer and another 
coil. The timer or contact maker is sometimes referred to as an 
interrupter, though this is not technically correct as its function is 
first to close the circuit. 

SOURCES OF CURRENT 

LTp to about 1905, batteries were universally relied upon in this 
country for ignition work, the only exceptions to this being a few 
high-priced imported cars, some of which had magnetos operating 
low-tension systems with the so-called make-and-break spark plugs, 
while one or two, notably the Panhard, was equipped with the 
Eisemann magneto, designed to operate a non-vibrator coil. The 
writer imported the second of these magnetos to be brought into this 
country in the latter part of 1902, but the principles of its operation 
were so little understood, despite the fact that the magneto had 
been used in hand-ringing telephones for a generation, that auto¬ 
mobile designers were frankly skeptical regarding it, and only the 
few electrical men then in the industry had the slightest conception 
of its possibilities. In fact, Mr. J. M. Packard, then head of the 
Packard Company, was the first man out of dozens to whom it was 
shown to realize what the magneto meant to automobile ignition. 

CHEMICAL SOURCES OF CURRENT 

Primary Batteries. In the face of the advent of the magneto 
(1902), the majority of American designers preferred to stick to the 
battery, usually the dry cell. The term dry cell is really a mis¬ 
nomer, since a cell of this type consists simply of a zinc element con¬ 
stituting the case of the cell, a carbon element centered within this, 
and an electrolyte composed of a moist paste of suitable chemicals. 
The top of the cell is commonly sealed with pitch or wax compound 
to prevent the moisture from evaporating, and if by any chance the 
cell does become really ‘‘dry”, its usefulness is then at an end. 

Defects of Dry Cells, The chief defect of the dry cell is that it 
is an “open-circuit” battery, that is, the circuit is normally open 
and when closed for a brief period the cell will produce a heavy cur- 




ELECTRICAL EQUIPMENT 


87 


rent, at a low voltage, i.e., volts on the average. But to enable 
it to do so, the time of contact must be brief and the periods of rest 
frequent. Otherwise, the cell becomes '^polarized’’. The hydrogen 
generated as the zinc element passes to the carbon element in such 
volume as to completely cover and insulate it from the active material 
of the cell, consisting of a solution of sal-ammoniac and water. The 
use of a depolarizer, usually manganese dioxide, prevents this to a 
certain extent, but not sufficiently to avoid having the current 
output of the cell fall off very rapidly if the contact exceeds a few 
seconds. But as soon as the circuit is broken again, the hydrogen is 
rapidly dissipated and the cell is said to recuperate. It was the 
marvelous ability of the dry cell to recuperate rapidly after having 
been run down to a point where it no longer produced sufficient 
current to pass a spark at the plug, that led to so much dissatisfaction 
and to such a misunderstanding of the gasoline engine in the earlier 
days. With the extremely wasteful contact makers then used, a 
set of cells would run an engine satisfactorily for an hour or so, then 
it would begin to miss firing badly and soon stop. Inspection would 
reveal no sign of current. If a new battery were installed, the 
engine would again run satisfactorily, and the motorist usually 
decided that the old cells were “dead”. If, however, the inspection 
consumed ten or fifteen minutes, the battery recuperated and upon 
being cranked the engine again ran, only to repeat the performance 
a short time later. 

Liquid Batteries. The dry cell is, of course, one form of primary 
battery, this term being used to distinguish it from other forms in 
which the exciting chemicals are in liquid solution. Few attempts 
have been made to employ the latter type of battery for automobile 
ignition, due to the violent agitation of the liquid which would neces¬ 
sarily ensue from the vibration and jolting. The Edison-Lalande 
cell and a few others of similar character, in which the charging 
chemicals were supplied in convenient units ready for quick replen¬ 
ishing wLen the battery “died”, were tried in isolated instances but 
never met with general application, except on the motor boat, where 
the Edison-Lalande cells have been widely used. 

Storage Cells. The construction and advantages of the storage 
cell as well as its operation and handling are detailed at length in 
the section on “Electric Vehicles”. Due to its ability to provide a 


88 


ELECTRICAL EQUIPMENT 


very much greater supply of current, it soon displaced the dry cell 
on all except the then lower-priced cars. While it represented a 
great improvement, the wastefulness of the contact maker and of 
the coil vibrators proved too much of a drain on even the storage 
battery, and it was accordingly displaced by the magneto. Since 
the general adoption of the latter, batteries have been wholly dis¬ 
carded except as a source of starting current, for the magneto does 
not generate sufficient current at a low speed to make it possible to 
start the motor without ^^spinning” it, which calls for considerable 
manual effort. Magneto practice is given in a succeeding section. 

VOLTAGE AND SPARK CONTROL DEVICES 

Changes in Ignition Methods. Up to a few years ago, it was 
generally considered that the magneto practically represented the 



Fig. 43. Roller Contact Timer (Horseless Age) 


ultimate type of ignition current generator and that batteries would 
never play anything but a secondary role. Small diredt-current 
dynamos had been tried in a number of instances, chiefly prior to 
the advent of the magneto, but they were not then sufficiently 
developed for this form of service and proved quite as unreliable 
as the dry cell. The magneto was entirely dependable, made possi¬ 
ble much greater speeds, and had few shortcomings, none of which 
were of a serious nature, so that its position was deemed impregna¬ 
ble. This was prior to the successful development of electric-light¬ 
ing dynamos on the automobile, and more particularly the combined 
lighting and starting systems which are now in such general use. 



















































ELECTRICAL EQUIPMENT 


89 


The latter, in conjunction with improved forms of contact makers, 
has been responsible for bringing about a reversion to former practice 
with improved equipment. 

Contact Makers or Timers. Roller Contact Timer. It was 
largely due to the crudity of the timing device that so much diffi¬ 
culty was experienced with early ignition systems. As the term 
indicates, the timer closed the circuit through the coil at exactly the 
moment necessary to produce the spark in the cylinder ready to fire. 
But the long wiping or rolling contact usually employed was so 

wasteful of current that it quickly 
exhausted even a storage battery. 
Fig. 43 shows a roller contact 
timer. The coil vibrators were 
another serious source of loss. 

Atwater - Kent Interrupter. 
The difficulties with roller con¬ 
tact led to the adoption of a 
totally different principle em¬ 
bodied in the Atwater-Kent in¬ 
terrupter, Fig. 44. This affords 
an exceedingly brief contact with 
an abruptness of the making and 
breaking of the circuit that is not 
secured with any other device. 
The effect is to produce a strong current surge and a heavy spark, 
but of the briefest possible duration. 

The advantage of the brief duration is that great current econ¬ 
omy is realized. The fact that only one spark is required for each 
ignition is an important contributing element to this economy. 

With the Atwater-Kent interrupter, embodied in a distributor 
termed the “LTnisparker”, it is possible to run a car much further on 
a set of dry cells than could formerly be done with a storage bat¬ 
tery, two to three thousand miles on four or five dry cells being 
nothing uncommon. This has led to the development of other 
devices along similar lines, and, with the unfailing source of current 
now provided by the lighting dynamo and the storage battery 
which forms part of the system, battery ignition has been raised to 
a level where it is now almost the equal of the magneto. But before 



Fig. 44. Atwater-Kent Interrupter 

Atwater-Kent Manufacturing Wor^•s, 
Philadelphia, Pennsylvania 





















90 


ELECTRICAL EQUIPMENT 


making further mention of that phase of the subject, it is necessary to 
refer to the coil in order to give a clear understanding of the matter. 

Coils and Vibrators. Function of the Coil. Mention has 
already been made of the function of the induction coil or trans- 
former in stepping up the voltage of the current in order that it may 
bridge the gap in the spark plug. A coil is also employed in connec¬ 
tion with a low-tension system, but it is simply a single winding on 
an iron core which intensifies the current by what is known as self- 
induction. Though it raises the voltage by what may be termed 
the accumulation and sudden release of electrical energy acting in 
conjunction with a magnetized core, due to the sudden making and 
breaking of the circuit, it is not an induction coil as that term is 
ordinarily employed. 

As shown by Fig. 42, the latter has two distinct windings, one of 
a few turns of comparatively coarse wire and the other of many 
thousand feet of exceedingly fine wire, with high-grade silk insula¬ 
tion. After completing the coil, consisting of two superimposed 
windings and an iron-wire core passing through their center, it is 
placed in a wood box which is filled with melted paraffine wax which, 
upon solidifying, greatly enhances the resisting i)ower of the insula¬ 
tion to breakdown, due to the great difference in potential between 
various parts of the secondary winding. To set up an induced 
current in the secondary winding, the primary circuit must be 
quickly opened and closed. 

Necessity for Vibrator. The breaking of the primary circuit is 
accomplished by the use of a vibrator, a typical form of which is 
illustrated at E, G, and //, Fig. 42. This consists simply of the thin 
blade of spring steel at E, provided with an armature at the free end 
to intensify the attraction of the coil 11, and adjacent to the adjust¬ 
ing screw at G, by which the distances between the contact points 
can be accurately set. In addition to these elements it is usual to 
provide a screw adjustment for increasing or reducing the tension 
of the vibrator blades. 

Contacts in the best vibrators are made of platinum, or, better 
still, of platinum-iridium alloys, which are very hard as well as 
extremely resistant to the very high, though brief and localized, tem¬ 
peratures of the small arcs that form across the terminals each time 
the contacts are separated. In cheaper coils, German silver, silver. 


ELECTRICAL EQUIPMENT 


91 


and other metals often are much used for contact points, but the 
only advantage of these over platinum or platinum alloys is their 
lower price. 

Complication of Multi-Vibrator. A vibrator coil is necessary 
for each cylinder, each coil being energized as the timer passeg over 
the contact corresponding to it, thus putting it in connection with 
the battery at the moment that particular cylinder is to fire. Fig. 
45 shows a four-unit coil, i.e., for a four-cylinder motor. However, 
the coil cannot act before its core becomes ‘^saturated’’, that is, 
thoroughly magnetized, and it must then pull its armature down 
against the tension of its spring, so that there is both an electrical 
and a mechanical lag, or, in other words, an appreciable amount of 
time elapses between the moment the circuit is closed by the timer 

and that at which it is again 
broken by the vibrator to 
cause the spark in the cylin¬ 
der. A delicate adjustment 
is most sensitive and mini¬ 
mizes the lag besides econo¬ 
mizing on current, but it is 
difficult to maintain. A stiff 
adjustment, on the other hand, 
will remain operative for a 
longer time, but its greater 
inertia makes the motor sluggish in action while the current con¬ 
sumption is increased several times over. Despite the use of plati¬ 
num contact points, the heat of the spark is such that the latter 
burn away rapidly, necessitating frequent adjustment. As it is next 
to impossible to adjust four or six vibrators so that they will operate 
uniformly, it will be apparent why the vibrator coil was given up as 
soon as the magneto demonstrated that it was not a mystery beyond 
the understanding of the average motorist. The vibrator coil is 
accordingly obsolete and but for the fact that its existence has been 
extended by the Ford, it would probably be unknown to the majority 
of present-day motorists. 

Master Vibrator. To overcome the shortcomings of the four- 
unit vibrator coil, it is necessary to add a fifth coil. The latter is 
fitted with an especially sensitive and well-made vibrator which 



Fig. 45. Pittsfield Multi-Vibrator Coil 

Courtesy of Pittsfield Spark Coil Company, 
Dalton, Massachusetts 




92 


ELECTRICAL EQUIPMENT 


takes the place of the four vibrators on the original coils, so that 
the extra coil is termed a master vibrator. In operation, all four of 
the original vibrators are screwed down hard so as to make a per¬ 
manent connection, and the fifth coil is connected in the primary 
circuit so that the action of its vibrator breaks the circuit in the 



primary of each one of the coils in turn. It is accordingly only 
necessary to adjust a single vibrator, and regardless of whether this 
adjustment be good or bad, it is uniform for all four cylinders so that 
they fire with the same timing. But at the best, the arrangement is 
only a makeshift as the vibrator coil long ago 
ceased to have any legitimate excuse of exist¬ 
ence on the automobile. 

Non-Vibrator Coil. As the term indi¬ 
cates, this is simply an induction coil minus 
the vibrator. But instead of using four coils, 
as with the vibrator type, a single coil is em¬ 
ployed, and a distributor is inserted in the 
secondary or high-tension circuit. The essen¬ 
tials of such a system are shown by Fig. 46, 
a battery being indicated as the source of cur¬ 
rent. The timer C is driven by the camshaft 
of the motor so that the battery circuit is suc¬ 
cessively closed and opened in the usual firing order of the cylinders, 
four contacts being made for each two revolutions of a four-cylinder 
four-c\ cle motor. The contact is of sufficient duration to permit the 
coil to 'Tuild up”, i.e., to have its soft iron core become thoroughly 
magnetized, and is then quickly broken. At the instant that the latter 
occurs, the finger J of the distributor is passing the contact of the 



Fig. 47. Atwater-Kent 
Distributor 

































ELECTRICAL EQUIPMENT 


93 


cylinder F to be fired. The timer and distributor must accordingly 
be driven synchronously, so that the contacts in both occur 
simultaneously. This is accomplished by combining them in a 
single unit, as shown in Fig. 47, illustrating the Atwater-Kent 
“Unisparker”,. or as in the various types of magnetos illustrated 
further along. 

Limitations of current supply having been overcome by the 
ad()})tion of the magneto or the storage battery kept charged by the 
lighting dynamo, non-vibrator coils are usually wound to a higher 
resistance than the old vibrator coils, so as to produce a current of 
higher tension in the secondary. As tliis type of coil requires no 
adjustment, it is generally installed horizontally with its face flush 

with the dash, and on this face 
is mounted the switch giving 
three control points, i.e., neutral, 
battery (for starting), and mag¬ 
neto. The Remy dash coil. Fig. 
48, is a typical example. 

Distributor. This is simply 
a modification of the timer, de¬ 
signed to handle the high-tension 
current, or to distribute it to the 
different plugs. It takes the place 
of the multi-unit coil in which an 
independent coil is employed for each cylinder. Owing to the high 
voltage of the secondary current, actual contact is not necessary in a 
distributor, a small gap or clearance presenting no obstruction to 
the passage of the high-tension current, so that wear at this point is 
avoided. In the earlier types, a brass arm passing close to contact 
])oints, or sectors embedded in hard rubber, was usual. Carbon 
brushes making contact against the disk by means of light springs, 
were subsequently adopted and are now commonly used. As the 
carbon is very hard and its contact surface becomes glazed by the 
friction, the wear is practically negligible. The complete wiring of 
a distributor system is shown in Fig. 46. II is the ground or common- 
return connection of the secondary circuit and A. is the connection 
to the distributor 7, from which the high-tension current is distrib¬ 
uted by the arm J to the spark plug leads 77, E, 7, and C, 



Fig. 48. Remy Single Non-Vibrator Coil 
Showing Method of Installation 




















94 


ELKCTRICAL EQUIPMENT 


Condenser. The condenser is technically known as an electrical 
^‘capacity’’ in that it has the ability to absorb a quantity of elec¬ 
tricity proportioned to the area of its conducting surfaces and to the 
nature of the dielectric employed. This property is utilized to absorb 
the excess current passing at the moment the primary circuit of the 
ignition system is opened by a vibrator, thus bringing about a quick 
cessation of the current flow and preventing the destructive arcing or 
burning that would otherwise occur at the contact points. The 
charge thus absorbed is immediately returned to the circuit in the 
form of a discharge, when the ])()ints come together again and a 
higher potential value is impressed iqx)!! the current. A condenser 
consists of conducting surfaces placed between insulating surfaces, 
known as the dielectric. For ignition work, the conducting surfaces 
are sheets of thin tinfoil cut 
with conducting tabs which 
project beyond the ends of 
sheets of paraffined paper on 
which the tinfoil is placed. 

Between each two sheets of 
paraffined paper is placed a 
sheet of tinfoil, the latter 
being arranged so that the 

tabs project at alternate ends, Condon,er 



Fig. 49. The paraffined paper 

overlaps the tinfoil all around to the extent of an inch or more to 
prevent a discharge over the edges of the sheets. The capacity of the 
condenser depends upon the number and the size of the sheets of 
tinfoil and the thinness and the character of the dielectric separating 
them; and, when a sufficient number have been assembled, the pro¬ 
jecting tabs at each end are riveted or clamped together and a 
flexible wire lead connected to each. It is then connected in mul¬ 
tiple with the vibrator, and, in the case of a coil is inserted in the 
containing case of the latter and further insulated as well as held in 
place by having molten paraffine poured around it so as to fill the 
space. A condenser practically eliminates sparking at the contact 
points and is also used with the contact breaker of a magneto. 

Spark Plugs. No small part of the trouble experienced with 
early ignition systems was due to the defective design of the spark 








ELECTRICAL EQUIPMENT 95 

plugs employed. Where an over-rich mixture is delivered by the 
carbureter, i.e., one containing too much gasoline in proportion to the 
air, a certain amount of the carbon is unburned and remains in the 


Fig. 50. J-D Spark 
Plug 


Fig. 51. V-Ray 
Spark Plug 


Fig. 52. Open-Point 
Spark Plug 


cylinder in the form of soot. This is greatly increased by an excess 
of lubricating oil finding its way into the combustion chamber. The 
heavier carbons of this burn to the same consistency and are also 

deposited on the piston head, cylin¬ 
der walls, valves, and other exposed 
surfaces in the form of a fliiit-hard 
coating. The end of the spark plug 
receives its share and, as the carbon 
is an excellent conductor, the plug 
is accordingly short-circuited, so 
that the current, instead of jumping 
the gap between the points, takes a 
path of lower resistance across the 
carbon-coated insulating surfaces. 

Fundamental Requisite. The 
spark plug is the ^‘business end’’ of 
the ignition system and no matter 
how elaborate or efficient the essen¬ 
tials of the latter may be, its successful operation is governed 
entirely by that of the plug. x\s originally designed, the insulating 
material filled the shell at the sparking end, affording a direct path 


Fig. 53. Multi- Fig. 54. Chambered- 
Point Spark End Spark 

Plug Plug 





















96 


ELECTRICAL EQUIPMENT 


for the current as soon as this small surface became covered with 
carbon. Failure was accordingly frequent, it being nothing unusual 
to have to clean such a plug in less than fifty miles of running. To 
overcome this, a recess was allowed between the insulation of the 
central electrode and the outer shell. This simple expedient con¬ 
stitutes a basic patent (Canfield) under which all spark plugs are 
manufactured. Porcelain, mica, or artificial stone is used as the 
insulating material, the first-named being most generally employed. 
This is made in various forms, as shown by the sections. Figs. 50 and 
51, and it will be noted that the smaller diameter of the insulated 



Fig, 55. Bosch High-Tension Spark Plug 


electrode in the center greatly increases the area of the surface of 
both shell and porcelain that must be coated with carbon before a 
path is formed for the current. 

Electrode Arrangement. Practice also varies considerably in 
the arrangement of the electrodes, taking the form of open points as 
in Fig. 52, a bridge as in Fig. 50, or a number of points as shown in 
Figs. 51 and 53. In some instances, the central electrode is enclosed 
in a chamber, the gas entering through a small hole in the shell, as 
shown in Fig. 54. Considerable advantage is claimed for the type of 
plug having a plurality of gaps, the number usually being three, as 
shown in Fig. 55, or four as in Fig. 53. It is more theoretical than 
actual, however, as the current always takes the shortest path and the 





ELECTRICAL EQUIPMENT 


97 



bridging of any one of the gaps by a particle of conducting material, 
such as carbon, short-circuits all of them. 

Series Plugs. As shown in the various wiring diagrams, the 

shell of the plug is one of the electrodes and 
forms a part of the circuit by being screwed into 
the cylinder, the latter constituting part of the 
common ground return for both the primary 
and the secondary circuits of all ignition sys¬ 
tems. Experiment has shown a slightly in¬ 
creased power resulting from the simultaneous 
occurrence of two sparks in different parts of 
the combustion chamber of the cylinder, espe¬ 
cially with the T-head type of cylinder in which 
the two plugs can be located in the oppositely 
placed valve ports. This is termed double¬ 
spark ignition and the type of magneto de¬ 
signed for this purpose is described in the 
section on ^‘Magnetos’k To obtain the same 
result with the standard ignition circuit designed 
to produce but one spark in each cylinder, what 
is known as a “series” type of plug has been developed. One of these 
is shown in Fig. 56. In this the spark occurs between two central 

electrodes, as shown, the shell not forming a con¬ 
nection with the cylinder. The lead from the dis¬ 
tributor is attached to one of the binding posts of 
this plug and a second wire connected to the other 
binding post is led to a standard type of plug, thus - 
completing the circuit and placing both plugs in 
series so that a spark occurs simultaneously in 
bcth. By means of an attachment as shown in 
Fig. 57, this type of plug can be used with a 
grounded return, the arm shown connecting the 
shell in the circuit. As the majority of motors now 
in use have L-head cvlinders, and even at the best 
the advantage gained is very slight, the use of 
series plugs has not a great deal to recommend it. 
Magnetic Plugs. With a view to overcoming the defects of 
the mechanically operated make-and-break plug as used on low- 


Fig. 56. Series-Type 
Spark Plug 



Fig. 57. Method of 
Converting Series Plug 












































98 


ELECTRICAL EQUIPMENT 


tension ignition systems, an automatic plug 
was developed. As shown by the section, 
Fig. 58, this is simply a solenoid A and 
plunger C, the latter being held in contact 
at Z) by a spring B. The current passing 
through the winding A lifts the plunger 
and the spark occurs at D. The remainder 
of the system consists of a low-tension mag¬ 
neto or other source of current supply and a 
timer. Such plugs have been used to some 
extent on stationary engines, but have not 
proved practical on the automobile motor, 
as the high temperatures drew the temper 
of the plunger spring and often burned out 
the insulation of the winding. 

Priming Plugs. For low-priced motors, 
such as the Ford, which have no pet cocks 
or compression-release cocks on the cjdin- 
ders, a spark plug combined with a pet cock, 

such as that shown in 



Fig. 58. Low-Tension Magnetic 
Spark Plug 



Fig. 59. Priming Typo 
Spark Plug 


Fig. 59, can be had. These are usually known 
as “priming” plugs in that they permit of 
priming the cylinder with gasoline to render 
starting easy in cold weather. 

Waterproof Plugs. Ignition systems, on 
motor-boat engines in particular, are apt to 
suffer short-circuiting from spray or dampness, 
though this often happens on the automobile 
as well in heavy rainstorms. To guard against 
this a so-called waterproof type of plug is 
provided. The precaution usually takes the 
form of a hood of hard rubber or other insu¬ 
lating material placed over the connection, as 
shown in Fig. 60. 

Plug Threads. European practice has 
standardized a straight-threaded plug, the 
thread itself usually being of fine pitch. A 
plug of this kind is screwed home on a gasket 




























































ELECTRICAL EQUIPMENT 


99 


of copper and asbestos or of the latter material alone, which is relied 
upon to prevent leakage. Foreign types are usually referred to as 
metric” plugs, as the thread dimensions are based on the metric 
standard. As developed at first in this country, all spark plugs 
^\ere made with an iron-pipe” thread. This has a taper of three- 
fourths inch to the foot and the plug is 
screwed into the cylinder as far as the taper 
will permit, no other provision being made to 
hold the compression. As this is a crude 
expedient, adopted chiefly because of its 
cheapness, and the metric standard is not 
employed here, an S.x\.E. standard plug has 
l)een developed along the same lines, both the 
])lug diameter and the thread itself being 
made somewhat larger than those used 
abroad. 

Hydraulic Analogy in an Ignition System. 

A comparison of the workings of an ignition 
system with the action of an hvdraulic svstem 
having similarly related parts will serve to 
make clear the operation of the former. It 
must first be borne in mind .that a high-tension ignition system consists 
of a source of current; an interrupter, or method of automatically 
breaking the circuit of this current su})ply, timed with relation to 
the revolution of the engine crankshaft; a condenser to suppress the 
arc at the interrupter contacts; a transforming device, or induction 
coil, to transform a current of comparatively high amperage at a low 
potential to one of high voltage; a device for distributing this high- 
tension current to the spark plugs, also timed with relation to the 
crankshaft; and the spark plugs themselves. 

Current. The electric current in the ignition system may be 
represented by water flowing in a pipe from a source of supply which 
I)uts it under pressure, corresponding to the storage battery. A 
certain amount of frictional resistance must be overcome by the 
water in flowing through the pipe and this is equivalent to the 
electrical resistance of the wiring in the ignition circuit. The rate 
of water flow in the pipe corresponds to the current in the coil, and 
the inertia of the water to the inductance of the primary winding of 



Fig. 60. Spark Plug, with 
Waterproof Connections 






100 


ELECTRICAL EQUIPMENT 


the induction coil. Now, if the flow of water be suddenly stopped, 
there will be an enormous increase in the pressure, due to the inertia 
of the water. This effect, known as water hammer, is commonly 
noticed in the larger sizes of pipes carrying water under considerable 
pressure. It corresponds to the great increase in the pressure, or 
voltage, which takes place when the flow of current in the primary 
of the ignition circuit is opened suddenly by the interrupter. This 
is due to the inductance in the coil. x\ quick-closing valve in the 
water system would accordingly correspond to the timer contacts 
which interrupt the current in the primary of the induction coil. 

Office of Condenser. There is one peculiar tendency of timer 
contacts which must be mentioned here to make the analogy more 
complete. Ihiless protected by a condenser, they are apt to burn 
away very rapidly, due to the arc produced by the current at the 
moment of separation. (This is also true of the contacts of the battery 
cut-out and of the regulator employed in connection with starting and 
lighting systems; the condenser does not eliminate this tendency to 
burn away but reduces it to a minimum.) This failing on the part 
of the timer contacts would correspond in the hydraulic system to a 
valve with a very thin edge which would be liable to bend under the 
sudden rise in pressure before it is fully closed. In the case of both 
systems, therefore, it is necessary to arrange for some protection, 
and a condenser is supplied for this purpose in the ignition system. 

In the hydraulic system, it takes the form of a surge chamber, as 
shown in Fig. 61. This chamber has an elastic diaphragm centrally 
placed in it, and the chamber itself is shunted, or connected, around 
the valve in the same manner as the condenser is connected to the 
contact points. When the valve begins to close, this surge chamber 
relieves the pressure to some extent during the operation of closing 
the valve and so protects the thin edge of the valve from bending. 
After the valve is fully closed, there is, of course, no further danger 
of its being bent over. In the electrical system, the condenser 
supplies similar protection, reducing the voltage at the timer contacts 
at the moment of separation and keeping this voltage reduced until 
they are fully open, thus preventing the current from bridging the 
gap, or arcing. Once the contacts are fully separated, the low-tension 
current cannot jump the air gap, so that there is no further danger 
of their burning. 


ELECTRICAL EQUIPMENT 


101 


Transformer. In order to utilize the pressure produced by the 
sudden closing of the valve, it is necessary to provide some trans¬ 
forming device, such as a pressure chamber. This is illustrated in 
Fig. 61, and it will be noted that it is of a much larger diameter than 
the pipe. As the pressure in the chamber and the pressure in the 
pipe will both have some unit value (measured in pounds per square 
inch), the total pressure on the piston will be to the pressure in the 
pipe as the area of the piston is to the area of the pipe. By the use 
of a pressure chamber of large diameter, compared to that of the 
pipe, a very considerable force is applied to the piston, but the 



Fig. 61. Diagram Showing Hydraulic Analogy of Ignition System 


distance it will travel is very slight. (To simplify matters, the weight 
of the piston is disregarded in this connection.) 

It is likewise necessary to provide a transforming device in the 
ignition system, and, in the case of both magneto and modern battery 
systems, this is the induction coil, having a relatively large number 


of turns in the secondary winding and a comparatively small number 
of turns in the primary. (In the earlier battery system, a vibrating 
coil is used for each cylinder and there is no distributor, while in the 
true high-tension magneto, the coil is part of the armature winding.) 
Just as in the hydraulic system the increased area of the piston is 
responsible for the increased total pressure on it, so the large number 
of turns in the secondary of the coil give the very high voltage 
required to enable the current to bridge the air gap at the spark plugs. 



































102 


ELECTRICAL EQUIPMENT 


This high voltage is accompanied by a very small amount of current, 
just as in the hydraulic system the greatly increased pressure on the 
piston produces but a very slight movement of the latter. 

INDUCTION SOURCES OP IGNITION CURRENT—MAGNETOS 

Owing to the failure of either dry cells or storage batteries to 
supply sufficient current to operate the wasteful contact de\ ices at 
first employed, mechanically dri\'en current generators were adopted. 
American practice at first favored the small, high-speed direct- 
current dynamo, but as proper regulating devices had not then been 
developed, it was not successful, chiefly because its speed range was 
so limited. Few of these little dynamos generated sufficient current 
at less than 1200 r.p.m. to ignite the charge in the cylinder, so that 
at slow sjjeeds they would not run the motor. If run much faster, 
they burned out and were accordingly abandoned. 

Working Principle. The magneto is simply a small dynamo 
in which the fields consist of permanent magnets, instead of electro¬ 
magnets, the cores of which only become magnetic when a current 
is passed through their windings. Hard steel, particular!}" when 
alloyed with tungsten, retains a very substantial percentage of its 
magnetism, after having been once magnetized by contact with a 
powerful electromagnet. Its retaining power is further increased by 
placing a ‘‘keeper”, or armature, across the poles, or ends. The 
advantage of a permanent field for magneto use is that it is at its 
piston produces but a very slight movement of the latter. This rise in 
the voltage and decrease in the current can be made clear by a brief 
explanation. By the principles of induction, a current flowing in the 
primary coil will induce a current in the secondary coil. The energy 
of these currents in watts is ecpial to the electromotive force in volts 
times the current in amperes. Now, as the transformer cannot create 
electrical energy, the energy of the transformed current must equal 
the energy of the current before it is transformed, barring a small loss 
within the transformer. This means that if the voltage of the cur¬ 
rent is raised from 6 volts, say, in the primary to 6000 volts in the 
secondary, the amperage of the primary current must be correspond¬ 
ingly reduced from 2 amperes, say, to .002. In other words, the 
product of the current and electromotive force must be always the 
same before and after transformation. 


ELECTRICAL EQUIPMENT 


103 


maximum intensity regardless of how slowly the armature is revolv¬ 
ing so that a good spark is produced at very low speeds; while its 
initial value cannot be exceeded no matter how fast the machine is 
run, so that the armature winding cannot be burned out. All 
magnetos generate an alternating current so that 
when used with a coil there is no necessity of fre¬ 
quently making and breaking the circuit, as is done 
by the vibrator of a coil handling direct current, 
the alternate surges of current from zero to maxi¬ 
mum of opposite polarity producing the same effect 

more efficientlv. 

«■ 

Low=Tension Magneto. A low-tension magneto 

is nothing more or less than the simple instrument MagnSo Contact 
which formed part of the thousands of telephones Hreaker 

of the hand-ringing type still to be found in rural districts. Built 
with more powerful magnets and wound to give a greater current 
output at a lower voltage, it was employed in connection with low- 

4 

tension ignition systems. A magneto of this type is illustrated by 




Fig. 63. Contact Breaker of High-Tension Magneto (Bosch) 


Fig. 39. As the mechanically operated make-and-break plugs are 
timed, the magneto is simply revolved continuously without refer¬ 
ence to the motor timing, the current being constantly delivered to 
the circuit through the usual collector ring and brushes. Magnetos 














Fig. 04. Sectional and End Views Through High-Tension Magneto (Horseless Age) 









































































































































































































































ELECTRICAL EQUIPMENT 


105 


of this type are still used to a greater or less extent on large, slow- 
speed stationary engines. 

High=Tension Magneto. Essentially all magnetos are the 
same: that is, they have a permanent magnet field and a two-pole 
armature. In what may be best identified by terming it the true 
high-tension ty 2 )e, there are two windings on this armature, a primary 
winding of comparatively coarse wire in which the current is gener¬ 
ated, and a secondary winding of fine wire, the same as an induction 
coil. A magneto of this type is timed with the motor according to 
the number of cylinders, being driven at crankshaft speed in the 
case of a four-cylinder motor and at one and a half times crankshaft 
speed in the case of a six. In addition to the usual current-collecting 
device, it is equipped with a contact breaker or interrupter, such as 
that shown in Fig. 62, which is part of a Remy magneto. Fig. 63 
shows the same essential of a Bosch light-car type magneto. Except 
at the point in the revolution at which the spark is to occur in the 
cylinder, the armature circuit is normally short-circuited upon 
itself. This permits it to “build up”, so to speak; that is, as the 
armature poles come within the most intense part of the field, the 
current in the armature winding reaches its maximum value and, 
at this moment, the contact points of the breaker are opened and a 
strong current is induced in the secondary winding. As the dis¬ 
tributor runs synchronously with the contact breaker, the circuit 
to one of the plugs is closed at the same time the spark occurs at it. 

Description of True High-Tension Type. A sectional view of a 
true high-tension magneto is shown in Fig. 64. In this the primary 
and the secondary windings on the shuttle armature are entirely 
separate to insure better insulation. These windings are not shown 
in section in the illustration, the usual insulating tape winding being 
indicated on the armature. Twice during every revolution of the 
armature, the primary circuit is opened at the platinum points P P 
of the circuit breaker, the interruption occurring substantially at the 
moment when the primary current is at its maximum. From the 
primary winding, the current is conducted to the stationary member 
of the contact breaker C through the terminal B. A is the condenser. 
One terminal of the secondary winding is connected to the end of the 
primary winding, as-in a coil, and the other connects with the high- 
tension collector ring D, from which it is conducted through a carbon 


106 


ELECTRICAL EQUIPMENT 


brush to the brush of the distributor above it for distribution to the 
four brass segments in the distributor plate E. These segments are 
connected to tlie four terminals shown extending above the magneto 
in the end view at the right and from them the usual high-tension 
cables are led to the plugs. The distributor is driven from the arma¬ 
ture shaft of the magneto through 2 to 1 gearing so that it only 
makes one revolution for two turns of the crankshaft in the case of 
four-cylinder four-cycle motor, as in the latter but two explosions 
occur per revolution. To vary the time of occurrence of the spark in 

the cvlinders, the contact 
breaker may be turned 
through part of a revolution 
by means of a rod and 
linkage fastened to one of 
the extensions of the con¬ 
tact breaker box, as shown 
in the end view. This con¬ 
nects with the spark timing 
lever on the steering wheel 
and, to stop the action of 
the magneto, it is only 
necessary to move this lever 
to the extreme retard posi¬ 
tion, which brings the spring 
G in contact with the bolt 
II and short-circuits the 
secondary winding. 

The magneto. Fig. 65, 
differs from the section. Fig. 63, chiefly in detail. The vertical plug 
just back of the contact-breaker box incorporates the safety gap. 

Tyjncal High-Tension Magneto Circuit. Fig. 66 is the wiring 
diagram for a high-tension system, using a true high-tension type 
magneto. C and B are the wires of the primary circuit, in which cir¬ 
cuit there are also included, besides the current-generating coils of 
the armature, an induction coil built into the magneto, for raising 
the current tension, and a contact breaker E, which is carried on the 
same revolving spindle that bears the armature. The dotted lines 
indicate the ground return. 






ELECTRICAL EQUIPMENT 


107 


High-Tension Type with Coil. This is not actually a high- 
tension magneto, properly so-called, as it only generates a low-tension 
current, which is subsequently stepped up through a transformer or 
non-vibrator coil, but it is commonly so termed as it is always used in 
connection with a high-tension ignition system. In this case there is 
only a single winding on the armature and the current is led from the 
latter through the usual contact breaker and then to an independent 
coil, generally located on the dash. The condenser is combined with 
the coil, and from the latter the high-tension current is led back to 
the magneto to be distributed. Owing to its lower cost, this type of 



j 


c 


Fig. (36. Wiring Diagram of High-Tension Magneto System 



magneto is probably more generally employed, especially on medium- 
priced American cars, than any other. 

Safety Gap. If the current induced in the secondary winding of 
an induction coil meet with a resistance in the outer circuit in which 
the coil is connected, greater than the resistance presented by the 
insulation of its own windings, it will puncture this insulation and the 
expensive coil will be ruined. The placing of such a resistance in the 
high-tension circuit occurs when the connection of a spark plug is 
removed from the plug terminal and is allowed to dangle in the air 
beside the motor and, unless this were guarded against, it would 
result in the breakdown of the ignition system. The precaution takes 
the form of a safety gap. This is an opening inserted in the circuit, 
and its length is based on the safe maximum distance that the coil 






























































































108 


ELECTRICAL EQUIPMENT 


can bridge in normally dry air. A safety gap of this kind is shown at 
F in Fig. 64. In the type of magneto just described above it is 
embodied in the coil. When an opening at any point in the high- 
tension circuit exceeds the length of this gap, the current takes the 
path thus provided, thus preventing the imposition of an excessive 
strain upon the insulation of the secondary windings. 

Wiring Connections. For the actual operation of an induction coil, 
there is no necessity for any electrical connection between the primary 
and the secondary windings, the electrical energy being transferred 
from one to the other entirely by induction, i.e., through the inter¬ 
mediary of the magnetic lines of force which interlink both. How¬ 
ever, for the sake of simplicity of external connections, the beginning 
of the secondary winding is usually connected to the end of the 
primary. Both the primary and the secondary circuits have a 
^‘ground return”, which necessitates that one end of both the primary 
and the secondary winding of the coil be placed in positive metallic 
connection with the engine or car frame. By connecting the two 
windings, as mentioned, a single wire serves to ground both. The 
average coil, therefore, has only three terminals, i.e., one primary, one 
secondary, and one common ground connection. 

On cars that are provided with magneto ignition alone, as is the 
case with French taxicabs and many other French light cars, there 
would be only two connections between the magneto and the coil, 
one primary and one secondary; one connection from the coil to a 
ground, as the motor or frame; and four connections direct from the 
magneto distributor to the spark plugs. This represents an ignition 
system reduced to its lowest terms of simplicity. As a matter of fact, 
it is even more simple in reality, as most French cars use the true 
iiigh-tension type of magneto so that the four leads from the magneto 
to the plugs are the only external wires in evidence. Unless a mag¬ 
neto is in excellent condition, however—and the magnets lose their 
strength more or less rapidly under the influence of the heat and 
vibration—too much effort is required to start the motor. American 
manufacturers accordingly supply a battery for starting purposes, 
and on some of the high-priced cars this takes the form of an entirely 
independent battery ignition system, i.e., having a battery, coil, 
timer, distributor, and a separate set of spark plugs. It also con¬ 
stitutes an emergency system that may be resorted to in case of a 


ELECTRICAL EQUIPMENT 


109 


breakdown of the magneto, but the latter is so rare and the cost 
and complication of the extra system are such that the latter is not 
generally used. Instead, the magneto coil, contact breaker, and 
distributor are utilized with the battery as the source of current. 

Inductor=Type Magneto. Mention has been made in the intro¬ 
ductory of the fact that if a coil of wire be moved so as to cut the 
lines of force of a magnetic field, an e.m.f. will be induced in the 
wire. If, instead of moving the wire, a magnetic flux be made to 
pass through it first in one direction and then in the other, the same 
result will be obtained, i.e., an alternating e.m.f. will be produced, 



Fig. 67. Rotor and Winding of K-W Inductor Magneto 
Courtesy of K. W. Ignition Company, Cleveland, Ohio 


and, if the wires be connected to an outside resistance, a current 
will flow. This is the principle of the inductor magneto which is so 
termed because the current is induced in its winding instead of being 

directly generated in the latter. 

Typical Construction Details and Current Production, The 
magnetic field is produced by permanent magnets in the same 
manner as on other types of magnetos and a mass of laminated soft 
iron is rotated between the pole pieces while the winding is station¬ 
ary. The moving element is termed the rotor, and this part of the 
K-W high-tension magneto is shown in Fig. 67. The stationary 




110 


ELECTRICAL EQUIPMENT 


winding in the center is mounted on the shaft of the rotor and con¬ 
sists of a primary and secondary coil. 

There is no mechanical or electrical connection between the 
windings and the rotor shaft, nor between the laminated blocks of 
the rotor and the windings. As shown in the illustration these are 
placed at right angles to one another and are riveted to the shaft. 
It will be evident that in the position shown in the illustration the 
right-hand member of the rotor will be bridging the pole pieces of 



Fig. 68. Section through K-W Inductor Magneto 
Courtesy of K. IV. Ignition Company, Cleveland, Ohio 


the magnetic field; by giving the shaft a quarter turn the two rotor 
members will have their ends facing opposite poles of the magnetic 
field, thus completing the magnetic circuit through the center of 
the windings. Consequently, a current wave will be produced each 
time the rotor revolves through a quarter-turn, or 90 degrees, so 
that this inductor magneto produces four impulses per revolution 
instead of two as in the ordinary type having a wound bipolar 
armature of H form. Apart from the method of producing the 
current, the remaining essentials of the magneto are the same. 














































































































































ELECTRICAL EQUIPMENT 


111 


except that no collector brush is necessary as is the case where the 
current is generated in a revolving winding on an armature. 

The details of construction of the K-W high-tension magneto 
are shown in Fig. 68. While, from an external view of the rotor, 
it apparently consists of two independent parts, it will be seen in 
the section that it is practically one piece, the connecting part 
passing through the center of the winding so that the magnetic cir¬ 
cuit is completed through the latter. The primary winding, consist¬ 
ing of four layers of comparatively coarse wire, will be noted close 
to the rotor; just outside of this is the secondary winding of many 
layers of fine wire and from the latter the connection is carried 
upward to a horizontal strip of copper termed a bus bar. At the 
right, this bar connects with the distributor for the high-tension 

current; at the left it 
connects with the safety 
gap, directly beneath 
which is the condenser. 

Timing. The mag¬ 
neto is timed by an in¬ 
terrupter operated by a 
cam on the rotor shaft in 
the usual manner; the 
details of this interrupter are shown in Fig. 69. As is the case with all 
ignition magnetos, these points remain closed, thus short-circuiting 
the primary winding, until the current reaches its maximum, and then 
are opened suddenly, thereby inducing a current in the secondary 
winding. The firing point of the magneto is just as the contact 
points begin to separate, as shown in Fig. 69, which is exaggerated 
to make this clear. At the same moment, the distributor arm is 
passing one of the segments connected to a spark plug, as shown in 
Fig. 70, the firing order of the motor in this case being 1, 2, 4, 3. 
While the magneto produces four waves per revolution, these are 
not necessarily all utilized; the cam (c in Fig. 70) opens the inter¬ 
rupter twice per revolution, giving two sparks for each turn of the 
crankshaft, as required by a four-cylinder four-cycle motor. In 
a four-cylinder two-cycle motor, a four-sided cam would be 
employed thus producing four sparks per revolution. 

The letters on the illustration are: A contact breaker box; c cam; 








112 


ELECTRICAL EQUIPMENT 


P contact points of interrupter; R cam roller to lessen friction at that 
point; B distributor arm; S distributor segments; RH and LII refer¬ 
ring to the direction of rotation, as either right hand—also termed 
‘‘clockwise” or from left to right—and left hand, anti-clockwise. 

Dixie Magneto. Essential Elements; Circuits. While based on 
the inductor principle, this differs from an inductor type of magneto 
in that the pole pieces themselves are revolved and they do not 
reverse their polarity as in the case of an inductor or an armature. 

The rotating element of the Dixie is shown in Fig. 71; R is a 
brass block which prevents any magnetic flux flowing directly from 



N to S, which are the rotating pole pieces. The coil with its pri¬ 
mary and secondary windings is placed directly above this rotating 
element, in the hollow of the magnets, as shown in Fig. 72. At the 
right in the same figure is shown the relation between the rotor, the 
magnets, and the coil. It will be noted that the core of the coil C 
bridges the stationary pole pieces F and G and that the shaft of the 
rotor passes through the magnets in a plane at right angles to that 
of the usual magneto. The reversal of the magnetic flux, with 
varying positions of the rotor, is shown in the right-hand sketch of 
Fig. 72, and in Fig. 73. 



























































ELECTRICAL EQUIPMENT 


113 


The primary circuit of the Dixie is shown in Fig. 74; A being 
the core of the coil, P the primary winding, P the condenser, Z and 

y the points of the interrupter or 
contact breaker. The terminal Z) is 
a screw on the head of the coil, and 
the wire Z connects directly with the 
contact Y of the interrupter. Fig. 
75 shows the details of this inter¬ 
rupter, the housing of which is at¬ 
tached to the mounting of the wind¬ 
ings, while the details of the secondary circuit are shown in Fig. 
76. C is the end of the high-tension, or secondary winding of 



Fig. 71. Rotating Element of Dixie 
Magneto 




Fig. 72, Details of Dixie Magneto 
Courtesy of Splitdorf Electrical Company, Newark, N. J. 


the coil, which is connected to a metal plate D embedded in the 
hard-rubber end piece of the coil A. A small coil spring holds the 



Fig. 73. Diagram Showing Reversal of Magnetic Flux in Dixie Magneto 


connection F in contact with D and at its outer end F connects with 
J which is the distributor brush. The latter revolves, successively 
passing over the segments leading to the corresponding spark plugs. 


















































114 


ELECTRICAL EQUIPMENT 


But one of these segments is indicated by L, the dotted lines indicat¬ 
ing the completion of the circuit through the ground connections. 

Timing. As the contact-breaker box is attached to the mount¬ 
ing of the coil, the latter moves with it when the former is partly 



Fig. 74. Primary Circuit of Dixie Magneto 



Fig. 75. Dixie Interrupter 


rotated to advance or retard the occurrence of the spark in the 
cylinders, so that the opening of the contact points always takes 
place at the point of maximum current. This is shown diagram- 
matically in Fig. 77. As 
the contact points are 
opened by the revolution 
of the cam, it will be ap¬ 
parent that a movement 
of the mounting of these 
points with relation to 
the cam will alter the 
time at which they will 
operate. For example, 
assuming that the 
magneto is designed to run clockwise, moving the interrupter in the 
same direction as the rotation will cause the spark to occur later, as 
shown by the retarded position in the sketch, hloving the interrupter 
against the direction of rotation of the cam accordingly would 
cause the spark to occur earlier. The range of movement is approxi¬ 
mately 15 degrees each side of the neutral point indicated by the 
horizontal position of the lever on the breaker box; the dotted lines 
show how the firing point may be advanced 15 degrees or retarded 
an equal amount. The lever in question is connected by means of 
linked rods to the spark lever on the steering wheel. 






















































ELECTRICAL EQUIPMENT 


115 


Magnetos for Eight=Cylinder and Twelve=Cylinder Motors. It - 

will be evident that, regardless of the number of cylinders to be 
fired, the principles of current generation, transformation (to high 
tension), and distribution remain the same, so that a reference to 



Fig. 77. Diagram Showing Method of Timing Dixie Magneto 
Courtesy of Splitdorf Electrical Company, Newark, N. J. 


the models of the Dixie for eight-cylinder and twelve-cylinder 
motors will suffice to cover the modifications required by the increased 
number of cylinders. To keep the speed of the magneto down, the 
rotor is provided with four-poles instead of two, so that four impulses 
are generated in the windings per revolution. This permits of 



Fig. 78. Stationary Member of 12-Cylinder Fig. 79. Rotating Member of 12- 

Splitdorf Distributor Cylinder Distributor 


running the magneto at crankshaft speed for an eight-cylinder 
motor and at IJ times crankshaft speed for a twelve-cylinder motor. 

Compound Distributor, The contact breaker opens every quar¬ 
ter revolution instead of every half revolution—a cam with four 






























116 


ELECTRICAL EQUIPMENT 


lifting faces being provided for this purpose—and the distributor 
is provided with twice as many segments and spark-plug leads as a 
magneto designed for four-cylinder or six-cylinder motors. But as 
the contact segments of the distributor must be sufficiently long to 
permit of the distributor brush being in contact with them, regard¬ 
less of the point to which the ignition timing is advanced or retarded, 
it is impossible to place more than six contact segments in a circle 
without reducing the insulation between them to a point where 
there would be danger of the high-tension current jumping the ga]) 
and thus deranging the ignition. To avoid this a compound dis¬ 
tributor is employed, i.e., two distributors are combined, but instead 
of being placed on a flat surface as in the magnetos for a smaller 
number of cylinders, the segments are spaced around the inner 
periphery of a hollow cylinder. Two radial contact brushes are 
carried by the revolving member of the distributor, each of which 
makes contact with one of the sets of segments. Fig. 78 illustrates 
the distributor itself, while Fig. 79 is the revolving member. The 
radial brushes A2 and B2 of Fig. 79 are electrically connected to 
contact brushes extending laterally (/ll and Bl) from the revolving 
member. These brushes make contact alternately with the arms 
of a metal spider sunk flush in the end wall of the distributor, S in 
Fig. 78, with which the central pin of the distributor rotor D, Fig. 
79, also connects. The high-tension current from the windings is fed 
to this distributor rotor through the spring brush contact C. 

Path of Current. The path followed by the current is accord¬ 
ingly as follows: from the high-tension wdnding of the coil (not 
shown here) to the distributor rotor through the brush C; from 
brush D to the spider S: from S alternately through brushes Al 
and Bl to the distributor segments representing the inner and 
outer row of spark-plug leads, through the brushes A2 and B2. 
Brushes Al and Bl are so spaced that, when one is centrally in 
contact with an arm of the spider S, the other is midway between the 
second and third arms from the one with which contact is being made. 

The relation of the various members of the Dixie magneto will 
be clear upon reference to the sectional view. Fig. 80, showing one 
of the four-cylinder models. The contact breaker or interrupter is 
at the left-hand end of the rotor shaft; just above the rotor itself 
is the coil, while to the left of this is the distributor, 


r 

t’ 

ELECTRICAL EQUIPMENT 117 



Fig. 80. End Elevation and Section'of Dixie 4-Cylinder Magneto Showing Construction and Connections 

Courtesy of “The Horseless Age” 
























































































































































































118 


ELECTRICAL EQUIPMENT 

IGNITION SYSTEMS 
STANDARD TYPES 

Dual Ignition System. Bosch Type. The dual type of ignition 
system uses one coil and one set of plugs with either the battery or 
the magneto as the source of current supply, the magneto contact 
breaker and distributor being common to both. Fig. 81 illustrates 
the connections of a dual system. M ire Number 1 is in the low- 
tension circuit and conducts the battery current from the primary 
winding of the coil to the contact breaker of the magneto. Low- 
tension wire Number 2 is the grounding wire by which the primary 



circuit of the magneto is grounded when the switch is thrown to the 
“off” or “battery” position. \Yire Number S leads the high-tension 
current from the magneto to the switch contact, and wire Numl)er 
4 is the wire that carries the high-tension current from the coil to, 
the distributor. Number 5 leads from the negative terminal of 
the battery to the coil, and the positive terminal of the battery is 
grounded by Number 7; a second ground wire. Number 6, is con¬ 
nected to the coil terminal. The press button on the switch cuts in 
the battery circuit which includes a special vibrator on the coil which 
is employed simply for “starting on the spark”; i.e., when a charge 
of gas is left in the cylinders and the crankshaft has stopped with 


































































































ELECTRICAL EQUIPMENT 


119 









yyy/y^TTTT-. 




Courtesy of "The Horseless Age 













































































































































































































































120 


ELECTRICAL EQUIPMENT 


the pistons in the proper position for firing the next one in order, 
a spark in that cylinder will frequently start the motor. 

Remy Type, Prior to the general adoption of electric lighting 
and starting systems, the dual type of ignition system was almost 
universally employed on the lower and medium priced cars, many 
thousands of which are still in service. The Remy magneto, a sec¬ 
tion and end elevation of which are shown in Fig. 82, is typical of 
the class used for this service. The armature A is of the II or 
shuttle type, of laminated construction fitted with cast bronze, 
heads B. It carries a single winding, one end of which is grounded 
by connecting it to the rear bronze head at D, the ground connec¬ 
tion being further insured by the carbon brush E, pressed against 
the head by a spring. The other end of the armature winding is 
connected through an insulated stud F to the collector ring G from 
which the current is taken by a carbon brush in the holder II. 
From this brush a low-tension cable runs to the induction coil 
mounted on the dash. 

The other primary terminal of the coil is connected to the 
terminal I on the breaker box at the right-hand end of the magneto. 
This terminal, which extends through the breaker-box cover J of 
insulating material, forms an integral part of the contact screw K 
which carries one of the contact points of the interrupter. The 
other contact point is mounted on the free end of the lever Z, pivoted 
at its lower end and provided with a fiber contact block bearing 
against the cam M carried on the armature shaft. The contact 
screw Kj interrupter lever L, and its stud N are all supported on 
the metal plate V forming the interrupter base. This plate is sup¬ 
ported on a lateral projection from a disc secured to the forward 
end plate S of the magneto and is provided with the radial arm V, 
which is connected by jointed rods to the spark timing lever on the 
steering wheel. This permits of moving the breaker box through 
part of a revolution with relation to the cam on the armature shaft 
to,advance or retard the time of ignition, as explained later under 
Spark Timing. The interrupter lever L is grounded to the frame 
of the magneto through the stud N. The condenser 0 is placed in 
the armature cover plate and has one terminal connected to the 
stationary contact screw K and the other terminal grounded, so 
that it is shunted or “bridged” directly across the interrupter and 


ELECTRICAL EQUIPMENT 


121 


serves to minimize the spark or arc caused by the opening of the 
contacts. The condenser is sometimes combined with the coil. 

Details of Typical Distributor. Apart from slight variations in 
detail, the following description of the distributor is typical of all 
magneto distributors. At its right-hand end, the armature shaft, 
hig. 81, carries the steel pinion P, which meshes with the bronze 
gear Q having twice the number of teeth. Rigidly mounted in the 
bronze distributor gear Q is a carbon brush U carried in the holder 
T. This brush is pressed by its spring against the inner surface of 
the insulating cover of the distributor IF, in which are embedded a 
central contact block X and four or six (according to the number 
of cylinders) contact blocks YY, equally spaced about a circle. 
At their outer ends these contact blocks carry terminals for the 
attachment of the high-tension cables. As the distributor revolves 
it makes contact with the central block A" and all of the blocks Y Y 
in succession. 

Since the distributor gear Q has twice as many teeth as the 
armature pinion, it makes but one revolution for every two turns 
of the crankshaft (four-cylinder motor) and of the armature, the 
latter being driven at crankshaft speed. As the four-cjdinder 
motor fires only twice per revolution, it is only necessary for the 
distributor to make one complete turn for every two revolutions 
of the crankshaft. The distributor is so geared to the armature 
shaft that it operates synchronously with the interrupter, i.e., when¬ 
ever the contacts of the latter separate to open the magneto armature 
circuit and permit the current to flow through the primary of the 
coil, the brush U is on one of the contact blocks Y. The exact 
moment of opening is governed by the setting of the timing lever, 
but the distributor brush U is made of sufficient width to cover 
the contact block throughout the whole timing range. A feature 
of this model of the Remy magneto is the timing button Z fitted 
into the distributor cover, to facilitate the adjustment of the timing 
of the magneto to the motor. Most magnetos have to be discon¬ 
nected from the driving shaft to accomplish this. This button is 
normally held out by its coil spring. If the button is pressed in and 
the armature shaft is then turned, the plunger of the button will 
drop into a recess in the distributor gear. Then the engine must 
be turned over by hand until the piston of cylinder No. 1 is exactly 


122 


ELECTRICAL EQUIPMENT 


at the upper dead-center position at the beginning of the power 
stroke, and while the crankshaft of the engine and the armature 
shaft of the magneto are in these relative positions, the magneto 
driving gears must be meshed and the magneto gear secured on the 
tapered end of the armature shaft by means of a Woodruff key 
which is held in place by a bushing and nut, as shown in the sec¬ 
tional view. Fig. 82. 

Typical Wiring Diagram. Fig. 83 is a wiring diagram of a 
typical dual-ignition system that illustrates the connections in 
greater detail than in the case of the Bosch system. The switch 



Fig. 83. Wiring Diagram of Magneto and Coil in the Remy Dual Syf=ttem 

Courtesy of “The Horseless Age” 


shown just below the induction coil has three positions: “OFF” 
(central); “BATTERY” (left); and “MAGNETO” (right). When 
the switch is on the BATTERY contact, the current flows from the 
battery through the switch and the primary winding of the coil to 
the interrupter, and completes the circuit by means of the ground 
connection of the latter and the coil. The secondary current is 
distributed in exactly the same manner as when the armature of 
the magneto is supplying the low-tension current. As the inter¬ 
rupter has its contacts closed, except for the momentary break when 
the spark occurs, its demand upon the battery is large, so that the 




























































































123 


ELECTRICAL EQUIPMENT 

switch should immediately be shifted to MAGNETO as soon as the 
engine vStarts. Otherwise a dry-cell battery will be exhausted in a 
comparatively short time, or an unnecessary drain will be made 
from the storage battery where the latter is employed for starting. 

Duplex Ignition System. This is designed to facilitate the 
starting of the motor by utilizing the current from a battery as well 
as that from the magneto when cranking to start. To throw the 
battery current in phase with that of the magneto, it having pre¬ 
viously been stepped up to high tension through a coil on the dash, a 
commutator is fitted to the magneto shaft. The magneto is of the 



Fig. 84. Wiring Diagram of Boscli Duplex Ignition System 


true high-tension or independent type, and by means of this com¬ 
mutator the flow of battery current is in the same direction as the 
flow of magneto current, a change in the direction of one (alternating 
current as generated by the magneto) is accompanied by a change in 
the direction of the other, and they are said to be 'hn phase,” i.e., 
the cycles of alternation correspond in both. To accomplish this the 
battery current’s polarity must be the same as that of the magneto 
and the battery must not be grounded, as shown by the wiring 
diagram. Fig. 84. The necessity for using the battery current to 
supplement that of the magneto exists only at very low cranking 
speeds, and the assistance of the battery is no longer needed once 
the engine starts. This type is not in general use. 








































































































124 


ELECTRICAL EQUIPMENT 




Double=Spark Ignition. Mention has already been made of 
the employment of two sparks occurring simultaneously in 
the cylinders under the head of “Series Plugs”. It will be 
evident that simply by adding 
another distributor to a magneto 
and taking leads from it to a 
second set of plugs placed at 
another point in the cylinders, 
preferably as far awav from the 
first as possible, the same result 
is accomplished. Fig. 85 shows 
a Remy two-spark magneto, 
the distributors being mounted 

at opposite ends of the field. 85. Remy Two-Spark Magneto 


Fig. 86. Magnets of Ford Magneto 

Ford Magneto. The Ford magneto is sui generis. What the 
patent lawyers term the “prior art” shows nothing even vaguely 
resembling it and no ignition current generator used on either 





ELECTRICAL EQUIPMENT 


125 


American or foreign cars, past or present, can lay claim to any family 
ties. Not that its principles differ in any way, but their application 
is very unusual, and as this magneto is now employed on more 


Fig. 87. Ford Magneto as Installed 



than a million cars, it is of particular interest. Instead of the two or 
three horseshoe permanent magnets employed on the ordinary mag¬ 
neto, the Ford has sixteen magnets arranged radially with their 
poles outward, and all are bolted directly to the flywheel, as shown in 
Fig. 80. Directly in front of them and separated by a very small 



Fig. 88. Copper Ribbon Coils of Ford Magneto 


clearance are sixteen coils, wound of copper strip or ribbon and 
attached to a spider which is bolted to the crankcase of the motor 
just forward of the flywheel, as shown by Fig. 87. The spider itself 














126 ELECTRICAL EQUIPMENT 

and the coils are illustrated by Fig. 88, which shows one of the coils 
partly unwound at E. The spider and its coils remain stationary 
while the magnets are rotated in close proximity to them at high 
speed by the flywheel, thus inducing a current in the coil windings. 
The current is taken from the collector ring B, through the single 
brush C, the other side of the magneto circuit being grounded. Fig. 
*89 shows the complete ignition system as installed on the motor. 
The magneto is shown with part of its housing removed; at its upi)er 
center is the collecting brush mentioned, connected to the four-unit 


Fig. 89. Complete Ford Ignition System 

coil, which in practice is mounted on the dash. From the coil, four 
primary connections are made to the low-tension timer mounted at 
the forward end of the motor and driven from the camshaft, and the 
four high-tension cables for the spark i)lugs will be noted just below 
the primary connections. The other two binding posts on the back 
of the coil are for the current from the magneto and the ground con¬ 
nection. While a battery is ordinarily fitted in addition to facilitate 
starting, this can be accomplished on the magneto alone, as the latter 
is very powerful. Replacements are sold at such low prices that when 
the magnets have lost their strength, new ones often are inserted 
instead of remagnetizing the old, 








ELECTRICAL EQUIPMENT 


127 


C urrent SujJpIy and Distrihidion. Except for the use of a mag¬ 
neto to supply the current, the system will be recognized as the 
ordinary coil-and-battery type now long obsolete (1909 and earlier 
models). Instead of the direct current provided by a battery, how¬ 
ever, the hord magneto supplies an alternating current w^hich alter¬ 
nates sixteen times per revolution. Between each alternation, there 
is, of course, a momentary drop to zero so that, at the positions of 
the crankshaft and field magnets corresponding to this drop, there 
is no current in the armature, or so little that it is impossible to pro¬ 
duce a spark. Assuming that, when the timer completes the primary 



Fig. 90. Wiring Diagram for Ford Ignition vSystem 
Courtesy of "The Horseless Age" 


circuit, the magneto is at or very near the position of zero e.m.f., 
the coil vibrator will not respond as the current sent through the 
coil bv this very weak e.m.f. is not sufficient to operate it. As 
soon, however, as the current attains the minimum value necessary 
to attract the vibrator, a spark is produced. The result of this is 
that, as the spark timing lever is moved over its quadrant, the 
spark is not advanced uniformly with the lever motion. It doubt¬ 
less also accounts for the fact that the motor will often be found to 
run much better with the lever advanced but a short part of its 
travel, instead of at the point of maximum advance as is the case 
with the ordinary magneto or with the modern battery system. 
































































128 ELECTRICAL EQUIPMENT 

✓ 

Fig. 90 shows the wiring diagram of the Ford ignition system, 
the primary timer being indicated just above the magneto or gen¬ 
erator. To operate efficiently, this timer needs oiling daily when 
the car is in constant service, and in cold weather about 25 per cent 
of kerosene should be added to the oil used for this purpose, as the 
low temperature causes the latter to thicken. To the right of the 
generator are shown the switch, the four vibrator coils, and the 
spark plugs with their leads. As the magneto has but one collector 
brush, it is subject to few troubles. The collector brush may 
loosen up through vibration and may not make proper contact, or 
dirt and oil may collect on the ring against which it bears, with the 
same result. Apart from this, the chief trouble will be caused by 
weakening of the magnets. A current sent through the armature 
coils from an outside source will tend either to strengthen or to 
weaken their magnetism, depending upon the direction of the cur¬ 
rent itself and the relative position of the armature with regard to 
the magnets. As the armature is always likely to stop in swch a 
position that a current sent through it from an outside source will 
weaken the magnets, a battery should never be connected to the 
armature. 

Misfiring. Irregular firing can be traced most frequently to the 
timer and will be caused either by a lack of oil or an accumulation 
of dirt; with the timer in good condition, misfiring will most often 
be due to a lack of uniformity in the adjustment of the vibrators, 
or to worn and pitted vibrator contacts. With the motor running, 
the vibrator adjustment screws should be turned up or down very 
slowly until all four cylinders fire uniformly. Instructions for 
taking care of the vibrator points are given in detail in connection 
with the description of battery cut-outs and circuit breakers in 
Part III, Starting and Lighting Systems. Failure to fire is usually 
due to lack of contact at the collector brush on the magneto. The 
timer is so located that the primary cables get the full benefit of all 
oil and dirt, while its movement to advance or retard the ignition is 
also apt to abrade the insulation from these wires close to the timer, 
so that irregular firing may also be due to this cause. Complete 
wiring replacements may be had at such low cost that when the 
cables become oil soaked and their insulation worn, the easiest way to 
correct troubles from this source is to install a new set of connections. 



ELECTRICAL EQUIPMENT 


129 


SPARK TIMING 

Effect of Irregular Sparking. Like a steam engine, an internal 
combustion motor depends for its power output on the mean effec¬ 
tive pressure developed in the cylinder, usually referred to as its 
m.e.p. This is affected directly by three factors: first, the initial 
compression of the charge, that is, the pressure to which the piston 
compresses the gaseous mixture on its upward or compression stroke 
just before firing; second, the time at which the charge is ignited; 
and third, the length of the stroke. It is with the second factor 
alone that this phase of the ignition problem is concerned. In con¬ 
trast with the steam engine in which the steam as admitted is at a 
comparatively low pressure and expands gradually throughout the 
stroke, the pressure developed in the internal combustion motor at 
the moment of ignition is tremendous, but it falls off very rapidly. 
The impulse given the piston is more in the form of a sharp blow 
than a steady push, as with steam. The mean effective pressure 
developed depends very largely upon the pressure reached at the 
moment of explosion and this in turn depends upon the time ignition 
occurs with relation to the stroke. As the speed of an automobile 
motor varies over a wide range, it will be apparent that means must 
be employed for varying the time of explosion. To be most efficient 
it must occur at the point of maximum compression, i.e., when the 
piston is exactly at the upper dead center on the compression stroke. 
As both a mechanical and an electrical lag, or delay, must be com¬ 
pensated for, the setting which will give maximum efficiency at 500 
r.p.m. will be much too slow at 1500 r.p.m. and the spark would then 
nQt take place until after the piston had started down again and the 
pressure had dropped considerably, causing a great loss in power. 
On the other hand, an attempt to run the motor slowly with a spark 
timing that would give the best results at high speed would often 
result in causing the explosion to take place against the rising piston. 
This is evidenced by a hammering sound and a great falling off in 
the power. 

Advance and Retard. Means are accordingly provided-in the 
majority of ignition systems for causing the spark to occur earlier 
or later in the cylinders. This is termed advancing and retarding 
the spark, the nomenclature being taken from the French, with whom 
it originated. The explanation given in the preceding paragraph 


130 


ELECTRICAL EQUIPMENT 


for the necessity of this will make plain the car maker’s often repeated 
injunction to the novice—never to drive with the spark retarded. 
Another and equally important reason is that when operated this 
way, the combustion is incomplete, the gas continues to burn through¬ 
out the stroke, and a greatly increased percentage of its heat has to 
be absorbed by the water jackets, causing the motor to overheat 
badly. 

Adjusting for Time Factor of Coil. Every induction coil has a 
certain time constant, which represents the period necessary to com¬ 
pletely charge the coil, that is, the time required for the current in 
the primary winding to attain its maximum value. This time con¬ 
stant depends very largely upon the amount of magnetic energy 
which can be stored up in the coil. There must be added to this the 
time required to overcome the inertia of moving parts, such as the 
timer and the vibrators of a high-tension battery system, or the 
contact breaker and the distributor in a magneto high-tension 
system. As these parts are very small and light this would be 
practically negligible for any other purpose, but when figuring in 
hundredths of a second, as in the case of the ignition timing of high¬ 
speed multi-cylinder motors, it becomes of importance. The object 
sought, as already mentioned, is to have the spark always occur at 
the point of maximum compression. To accomplish this wdth the 
motor running at high speed, the ignition devices must act while 
the piston is still an appreciable distance below upper dead center. 
The timer in the case of a battery system, or the contact breaker of 
a magneto, is accordingly mounted so that it can be turned through 
part of a revolution with relation to its driving shaft, or more par¬ 
ticularly the cam carried by the latter. For starting the motor by 
hand, the spark must occur either at or after upper dead center is 
reached, never before. In the latter case, the piston would be 
driven backward and the familiar ‘Tack kick” result. Hence the 
manufacturer’s admonition—always retard the spark fully before 
attempting to crank the motor. 

Calculation of Small Time Allowance. The relation of spark 
advance in degrees to piston travel in inches with motors having 
strokes running from 3 to 8 inches is shown by the accompanying 
chart. Fig. 91. In this the ratio between the crank and the connect¬ 
ing rod length is 1 to 4.5. The lettering shown indicates the method 


ELECTRICAL EQUIPMENT 131 

of using the chart, the problem being to find the piston travel for an 
advance of 30 degrees in a motor of 6-inch stroke. The vertical line 
a, corresponding to this stroke, is traced upward until it intersects the 
30-degree line at c; following the latter to the left brings it out at a 



Fig. 91. Relation of Spark Advance to Piston Travel (Bosch) 

point just below the ^-inch division, or approximately .46 inch. 
Assuming that the 6-inch stroke motor were running at 1800 r.p.m., 
its pistons would be traveling 1800 feet per minute (i.e., stroke 
doubled or 1 foot per revolution), 30 feet, or 360 inches per second, 



















































































132 


ELECTRICAL EQUIPMENT 


so that each inch of the stroke would be covered at an average 
speed of 1 inch in of a second, and the J inch in of a second, 
from which the necessity for a timing allowance will be apparent. 

Magneto Timing. Timing is usually 30 to 40 degrees, which 
means that the spark occurrence can be advanced or retarded half that 
distance from a neutral line representing the upper dead center posi¬ 
tion of the piston. As shown by Fig. 92, the allowance is 34 degrees 
in the Splitdorf magneto, “left” and “right” in this connection having 



Fig. 92. Method of Advancing and Retarding Spark, Splitdorf Magneto 


reference to the direction in which the magneto armature is driven. 
The necessity of providing this allowance, however, introduces a 
complicating factor in magneto design. 

As the timing of the spark is accomplished by opening the 
contact points of the interrupter earlier or later, it will be apparent 
that as the magnetic field remains stationary in the ordinary magneto, 
the relative positions of the armature and field vary. This is illus¬ 
trated by the sketch. Fig. 93, the left-hand member of which shows 
the position of the armature with advanced spark. This is the point 
at which the current and voltage are at their maximum, so that the 
most efficient spark is produced at the plugs. With the spark 
retarded, the armature has already had time to turn practically one- 
















































































ELECTRICAL EQUIPMENT 


133 


eighth of a revolution and the point of maximum intensity has been 
passed. While this is a factor of which much is usually made in 
sales literature, it is not so important as the theory of the matter 
would make it appear, since the spark is seldom retarded except for 
starting. With the modern high-speed engine there is rarely sufficient 



Fig. 93. Position of Magneto Armature for “Advanced” and 
“Retarded” Ignition 


.0333 


slowing down in hill-climbing to make it necessary to retard the spark, 
while gear-changing at the proper time further makes this unneces¬ 
sary, so that practically all the time it is in service, the magneto 
is operating under the most efficient conditions. The great difference 
in the positions of the magneto armature between the advanced 
and the retarded points of the 
spark timing show why it is diffi¬ 
cult to crank a motor by hand 
with the spark retarded, when ^ 
relying upon the magneto for igni- 
tion. 

As already mentioned, most 
magnetos are fitted with bipolar 
armatures, i. e., there are two ex¬ 
tensions, or pole pieces, between 
which the winding is placed. This 
will be clear upon reference to 
Fig. 94, which shows the armature 
core of a Simms magneto. The phases are accordingly 180 degrees 
apart, that is, the current in the armature winding only reaches its 
maximum value twice per revolution, and as these maxima are really 
“peaks”, as shown by the oscillograph. Fig. 95, there is not much 



Fig. 94. Section Simms Magneto 
Armature and Pole Pieces 













































134 


ELECTRICAL EQUIPMENT 


leeway for variation one way or the other, if the greatest current 
value is to be utilized. 

Analysis of Oscillograph Diagrams. In the oscillograph, the 
dotted vertical line at the left represents the moment of closing the 
primary circuit, the current then beginning to. increase gradually in 
value. The resistance of this circuit is such that the current would 
attain a value of 5 amperes, if the circuit remained closed long 
enough. However, when the current has attained a value of 4 
amperes, the circuit is broken by the vibrator (battery and coil 
system) and the current then falls off very rapidly. It will be noted 
that there is no current in the secondary circuit while the primary 
is attaining its full value, which is due to the fact that the e.m.f. 



Fig. 95. Oscillograph Diagram of Primary and Secondary Currents 

{Horseless Age) 


induced in the secondary during this period is not sufficient to 
break down the resistance of the air gap in the spark plug. The 
spark oecurs when the primary circuit is broken, and it is interesting 
to note that it attains its maximum value instantly, this having been 
eonfirmed by numerous oscillograph tests. The right-hand dotted 
line represents the moment the primary circuit is broken by the timer. 
With a vibrator coil a series of sparks is produced, as compared with 
the single spark of the magneto, but these are of no advantage except 
at low speeds, as when running at full speed, if the first spark fails 
to ignite the charge, it is already too late by the time the second 
occurs. 

Oscillograph diagrams taken of the current and voltage of a mag¬ 
neto show that both rise to a sharp peak, first in one direction and then 
in the reverse, as the current is alternating. As the oscillograph illus- 























ELECTRICAL EQUIPMENT 


135 


trated shows that only tlie peak, or maximum, value of the current in 
the primary of the coil can be utilized for producing a strong induced 
current in the secondary, so the peak of the magneto current must be 
taken advantage of to produce the most efficient spark. This point 
of maximum current value in the revolution of the armature occurs 
when it is cutting the greatest number of magnetic lines of force of 
the permanent magnetic field, which is when it is just about to pass 
from the influence of one set of poles into that of the other, as shown 



Fig. 96. Mea Magneto in Trunnion Mounting 


in the section. Fig. 94. This also shows the relative positions of full 
advance and full retard and is designed to illustrate the advantages 
obtained with the patent extended pole pieces of the Simms mag¬ 
neto, most magnetos having the upper and lower faces of both poles 
in the same plane. 

Mea Method of Advancing Spark. Doubtless the most ingenious 
method of taking care of the necessity for advancing the spark has 
been developed in the Mea magneto, shown in Fig. 96. Instead of 
being of horseshoe form, as in the Bosch and Nilmelior magnetos, 
shown in Figs. 97 and 98, it is bell-shaped, as shown in Fig. 99. 
The entire magneto is carried in a trunnion mounting so that the 
field magnets may be turned to the same extent that the contact 
breaker is moved to give the necessary advance, thus insuring that 
the circuit will be broken with the armature in the same relative 



































































136 


ELECTRICAL EQUIPMENT 




position to the field poles, which is naturally that of maximum 
current value. 

The method of accomplishing this is shown in Fig. 100, which 
illustrates the relative positions of the armature and field magnets 
at the advanced and retarded sparking points to be the same, since 
the entire magnetic field is partly revolved about the armature. 

This movement is against the 
direction of rotation of the 
armature when advancing 
the spark, and with it when 
retarding the timing of the 
ignition, the illustration 
showing a magneto arranged 
to be driven clockwise. Fig. 
101 illustrates the position of 
the fields when looking at the 
driven end of the magneto 
for advanced and retarded 

Fig. 97. Bosch Enclosed Type Magneto Spark in both thc clockw ISC 

and anti-clockwise types. The 
range of timing varies from 
55 degrees to 70 degrees in 
the various models; and a 
specially long range totaling 
90 degrees to 100 degrees 
can be provided, if neces¬ 
sary, by increasing the over¬ 
all height of the magneto, as 
the shaft must be supported 
higher in the trunnions to 
permit of this. Among the 
advantages of this method 
of ignition timing are ease 
of starting without a bat- 
[ tery, quick acceleration, and 
a uniformly efficient spark 
at all positions of the spark- 

Fig. 98. Front View Nilmelior Magneto IcVCr. 






ELECTRICAL EQUIPMENT 


137 


Magneto Speeds. As the revolution of the armature of the 
magneto always bears a definitely fixed relation to that of the crank¬ 
shaft of the engine, it will be 
apparent that the speed at 
which the magneto is driven 
will depend upon the number 
of cylinders to be fired, as 
well as upon the relation of 
the cylinders to one another, 
i.e., firing 180 degrees or 3G0 
a part, as measured 
on the crankshaft. The fol¬ 
lowing are the various magneto speeds required for engines of the 
four-cycle type having from one to twelve cylinders : 

1- cylinder: Either crankshaft or camshaft speed 

2- cylinder: (Impulses 360® apart, as in 2-cylinder opposed motor) camshaft 

speed 

2- cylinder: (Impulses alternately at 180°, with 540° interval^, as in the 

2-cylinder V-type motor) camshaft speed 

3- cylinder: Three-fourths crankshaft speed 

4- cylinder: Crankshaft speed 

6-cylinder: One and one-half times crankshaft speed 

8-cylinder: Twice crankshaft speed 
12-cylinder: Three times crankshaft speed 

Owing to the extremely high speeds necessary, the modern 
battery type of ignition is favored to a great extent on eight- and 




Fig. 99. Bell-Shaped Magnets of Mea 
Magneto 



Fig. 100. Relative Position of Armature and Magnets at Moment 
of Sparking, in Mea Magneto 


twelve-cylinder motors, though magnetos are built even for the latter. 
(See description Splitdorf 12-cylinder magneto.) 























































138 


ELECTRICAL EQUIPMENT 


The magneto speeds necessary on two-cycle motors are twice 
those given above for the corresponding four-cycle types, with the 
exception that, on the 2-cylinder 180-degree or V-type motor, crank¬ 
shaft speed would be correct. 

lgnition=System Fixed Timing Point. It has become more or 
less general practice with French builders to provide an ignition 
system having a fixed timing point, i.e., one that cannot be con¬ 
trolled by the driver through the usual spark-advance lever as found 
on practically all American pleasure cars. This is particularly the 



Fig. 101. Spark Advance with Meo Magneto. With 
Clockwise Instruments, Position 1 Supplies Advanced 
Spark, Position 2 Retarded Spark 


case with taxicabs. While ‘‘fixed” in the sense that they are not 
variable while running, such systems have two firing points, one of 
maximum advance, which is always employed when the motor is in 
operation, and the other of maximum retard to enable the driver 
to crank the motor without danger of injury. So-called fixed-spark 
ignition systems have come into very general use abroad, more 
especially on the Continent, but have found very little favor here. 

Automatically Timed Systems. The stress laid by automobile 
manufacturers on their instructions, “always retard the spark before 
cranking the motor” and “always run with the spark advanced as 
far as possible, except when necessary to retard it owing to the motor 
slowing down on hills and causing a hammering noise in the cylinders”. 





















ELECTRICAL EQUIPMENT 


139 


make it evident that there is a considerable amount of discretion left 
in the driver s hands where this important point is concerned. It is 



Fig. 102. Armature with Centrifugal Timing Device, Eisemann Magneto 

not desirable that this should be exercised by unskilled drivers, 
particularly those in charge of large and costly commercial vehicles, 
and automatically timed systems have accordingly been developed. 



Fig. 103. Eisemann High-Tension Magneto with Automatic Timing 

Eisemann Centrifugal-Governor Type. To advance the spark 
timing automatically, a centrifugal governor has been mounted on 













140 


ELECTRICAL EQUIPMENT 


the armature shaft in the Eisemann magneto of this type, as shown 
in Fig. 102. Normally, the weights are contracted by the spring and 
the contact breaker is held at the fully retarded position, so that it 
is always safe to crank the motor without the necessity of taking 
any precautions. With an increase in speed, these weights tend to fly 
apart and in doing so they draw a sleeve and with it the armature 
along the shaft with them toward the left-hand end. As there are 
two helicoidal ridges on the shaft, however, and splines on the inner 

diameter of the sleeve engaging them, the sleeve 
is forced to make a partial revolution as it 
moves along the shaft, thus automatically 
advancing the ignition timing in accordance 
with the speed. The contact breaker is in 
fixed relation to the armature. An Eisemann 
magneto fitted with the automatic timing device 
is shown in Fig. 103. The lines drawn on the 
magnets indicate their polarity, so that in case 
the machine is taken apart it can readily be 
assembled again with the magnets in their 
proper relation. 

Herz Ball-Governor Type. Another method 
of accomplishing the same end is the Herz auto¬ 
matic coupling, shown in Figs. 104 and 105. 
This consists of two juxtaposed disks, each of 
which is provided with five grooves running in 
a direction opposite to those of the other disk. 
Five steel balls are held in these grooves and 
act like the weights of a governor, being forced outward in direct 
proportion to the speed of the motor, thus imparting a twisting move¬ 
ment to the magneto armature with relation to its shaft. The device 
is supplied either as an integral part of the magneto or as an independ¬ 
ent coupling. The range of movement is 40 degrees, the adjustment 
being varied by altering the curve of the grooves. Fig. 106 shows 
the Herz magneto. In the Eisemann, spindles having grooved slots 
of several different pitches are supplied, giving from 19 to 60 degrees 
of advance. The Atwater Kent, Connecticut, and Westinghouse 
ignition systems may also be had with automatic advance operated 
by a centrifugal governor. 



Fig. 104. Herz Automatic 
Spark Advance 
Coupling 



Fig. 105. Herz Automatic 
Coupling (Side View) 



ELECTRICAL EQUIPMENT 


141 


Ignition Setting Point. It will be apparent that as provision 
is made for advancing the time of ignition beyond a certain point as 
well as retarding it so as to occur before that point, there must be 
what may be termed a neutral position. This is usually referred to 
as the ignition setting point. In the majority of instances, this is 
the upper dead center, particularly where a magneto is employed. 
For the reason that it is possible to start the motor by handcranking 
on the magneto with the time of ignition advanced very much 
farther than would be safe with a battery, as explained in another 



Fig. 106. Herz Magneto 

section, it is seldom necessary to provide for retarding the ignition 
timing of a magneto past upper dead center. Consequently, the 
ignition setting point for the majority of magnetos is upper dead 
center when the spark-advance lever on the quadrant is at the point 
of maximum retard. It is not necessary to provide for what is termed 
a late spark, i.e., one occurring after the piston has actually started 
down on the power stroke, nor is it necessary to provide as great 
a range of advance in the case of the magneto as where a battery is 
employed, since the magneto, to a certain extent, automatically 
advances the moment of ignition as the speed increases. 





142 


ELECTRICAL EQUIPMENT 


Where a battery is employed, however, it is customary to allow 
a greater range of timing in both directions with a late spark to insure 
safety in starting, particularly by handcranking. The relation of 
the ignition distributor of a battery system to the crankshaft is 
shown in Fig. 107, which illustrates the ignition diagram of the four- 
cylinder Regal Motor. The firing order in this case is 1- 2- 3- 4, and 
it will be noted that the ignition setting point is upper dead center. 



Fig. 107. Relation of Ignition Distributor to Engine Crankshaft. 
Courtesy of Regal Motor Car Company, Detroit, Michigan 


Both the ignition and the valve timing of practically all motors built 
in recent years may be checked by marks on the flywheel. A corre¬ 
sponding mark or pointer on the crankcase is used as a checking point. 

Fig. 107 shows that when piston No. 1 is exactly at upper dead 
center, contact No. 1 of the distributor is under the brush leading 
to the spark plug of that cylinder, and, as shown by the center line, 
this is the ignition setting point for that motor. As the distributor 


































































ELECTRICAL EQUIPMENT 


143 


turns in a clockwise direction, rotating it toward the right, as shown 
in the diagram, retards the time of ignition, while turning it to the 
left advances it. The interrupter is just below the distributor and 
while its battery, ground, and distributor cables are shown, the con¬ 
tacts themselves are not illustrated. 

Upper Dead Center. In many cases it is no longer possible to 
check the ignition timing or the position of the pistons by the fly¬ 
wheel, as the latter is entirely enclosed. To And the upper dead 
center of the piston of the first cylinder it is accordingly customary 
to take out a spark plug and use a long knitting needle or similar 
piece of straight wire. While an assistant turns the motor over 
slowly by hand, watch the valves of cylinder No. 1. When the inlet 
valve of this cylinder has closed, the piston is traveling upward on 
the compression stroke and the needle will rise. It must be borne 
in mind, however, that the piston is not actually at upper dead 
center for ignition purposes when the needle ceases rising. In other 
words, a certain part of the revolution of the crank is not represented 
by a corresponding movement of the piston, and the proportion that 
this bears to the whole revolution naturally increases with the length 
of the stroke. 

The starting crank should accordingly be turned until the needle 
actually starts downward again on the firing stroke, and then the 
motor turned backward again slightly until it ceases to rise. This 
may be done by putting the gear lever in high, engaging the clutch, 
jacking up one rear wheel and turning it backward. This will give 
the proper ignition setting point for any system in which this point 
is given as “upper dead center with the spark at the point of maxi¬ 
mum retard”. But unless the precaution in question is taken, the 
spark timing will have a slight amount of advance and, in a long- 
stroke motor using a battery system of ignition, this may be sufficient 
to cause the motor to kick back when cranked slowly by hand. 

In some cases, where the flywheel rim is not accessible, the 
ignition setting point is marked on the distributor itself. 

FIRING ORDER 

Typical Firing Orders. It is naturally quite as important that 
the sparks occur in the different cylinders of a multi-cylinder motor 
in the proper order as that each individual spark should take place 


144 


ELECTRICAL EQUIPMENT 



Vie^v of Magneto Running Clockwise 

Distributor End Eiring 5eguence [. El. 17. U. 



View of Magneto Running Clockwise 

DislribulorEnd Seguence 1.7,17.01. 



View of Magneto Running Rnti - clockwise 

Di sin but or End Firing Seguence 1. El, 17,0. 



View of Magneto Running Finli-clockwise 

Dislnbulor End Firing Seguence 1.0.17,01 

Fig. 108. Firing Order of Four-Cylinder Motors 


(Bosch Magneto Company) 


at just the right moment. 
Regardless of the number 
of cylinders, the crank¬ 
shaft throws are always 
in pairs. Hence, the pis¬ 
tons rise and fall in pairs, 
and the cylinders of these 
pairs (which have no rela¬ 
tion whatever to the meth¬ 
od of casting the cylin¬ 
ders themselves) naturally 
cannot follow each other 
in firing, the firing order 
alternating from one pair 
to the other. For exam¬ 
ple, 1-3-4- 2- as in the 
upper diagram of Fig. 108, 
or 1-2- 4- 3- as in the dia¬ 
gram just below it, the 
motors in both these 
instances running “clock¬ 
wise”, i.e., with the crank¬ 
shaft turning from left to 
right. A similar variation 
is possible with the motor 
turning “anti-clockwise”, 
or from right to left, as 
shown in the two lower dia¬ 
grams, which show firing 
orders of 1-3- 4- 2- and 1- 
2- 4- 3- the changes being 
made by shifting the dis¬ 
tributor connections to the 
spark plugs of the various 
cylinders. In the case of 
a high-tension battery 
system using unit coils, 
the timer connections are 































































































































































































ELECTRICAL EQUIPMENT 


145 


varied in the same manner. In six-cylinder motors the crank throws 
are 120 degrees apart, but as the pistons are attached in pairs to cranks 
in the same plane, the method of distributing the firing order among 
them is similar to that already given. The Bosch dual ignition 
system, as installed on the six-cylinder Winton, is a typical firing 
order for a six. As shown by Fig. 109, this runs 1- 5- 3- 6-2-4. 

Possible Combinations. There are so many possible firing 
orders in the six-cylinder motor and likewise in the more recent 
eight-cylinder and twelve-cylinder motors that one of the most 
puzzling questions arising in the repair shop frequently has been 
to determine just which one has been adopted by the manufac¬ 



turer for his particular motor. So much uncertainty exists that 
many makers have solved this for the repair man by attaching a 
plate to the motor or to the dash, giving the firing order. There are 
eight firing orders possible for the six or eight. With the six these are: 

(a) 1 2 3 6 5 4 (e) 1 4 5 6 3 2 

(b) 1 2 4 6 5 3 (0 1 5 4 6 2 3 

(c) 1 3 2 6 4 5 (g) 1 4 2 6 3 5 

(d) 1 3 5 6 4 2 (h) 1 5 3 6 2 4 

While any of these firing orders will give an equally good impulse 
balance, the question of proper distribution of the incoming charge 
and the free escape of the exhaust also have an important bearing on 
the matter, so that the last two orders given are in most general use. 
The Winton Six, Fig. 109, shows the employment of order (h). 

















































































146 


ELECTRICAL EQUIPMENT 


For the V-type eight-cylinder motor, the possible firing orders 
are as follows: 


(i) IR IL 2R 2L 4R 4L 3R 3L (m) 

(j) IR IL 3R 3L 4R 4L 2R 2L (n) 

(k) IR 4L 2R 3L 4R IL 3R 2L (o) 

(l) IR 4L 3R 2L 4R IL 2R 3L (p) 


IR IL 3R 2L 4R 4L 2R 3L 
IR IL 2R 3L 4R 4L 3R 2L 
IR 4L 2R 3L 4R IL 3R 3L 
IR 4L 2R 3L 4R IL 2R 2L 


As the last four mentioned involve different firing orders in 
each set of four cylinders, they need not be considered. With the 
CYLINDER 


90 


80 


270 


360 


4 50 


540 


650 


750 


) 

R 

L 2R 2 

L 3 

R 5L 4 

R 4 

J 

1 






, 

1 














1 


§ 




1 ^ 

1 1 




c: 

0 




Center 






L 









[ 



1 



1 




J 

L 

1 

% 

. \ 


CS\ 

I 

U 


Working Stroke 
Exhaust " E 

Compress. " e 

Suction " c 



Operation Chart 



FIRING ORDER 

IR-4L-5R-ZL- 4R-IL -2R-ZL 
Eight Cgtinder 
90 Degree V Motor 


CrankPin Crankh'n CrankFin Crankhn 
Nod No. 2 Mo.S - NoA 


Fig. 110. Firing Order of Eight-Cylinder, V-Type Motor 
Courtesy of “Automobile Topics", New York City 

rocker-arm type of valve lifters using only eight cams, as in the 
De Dion (French, and the first to use an eight-cylinder motor), 
Cadillac, and King engines, it is only possible to use the orders k 
and 1 , while, as a matter of fact, all three employ the order given in 
1 , which is shown diagrammatically in Fig. 110. The other possible 
order for an eight (k) may be read from the same diagram by turn¬ 
ing it around and changing the numbers from 4L to IR, 3L to 2R, 



















































































ELECTRICAL EQUIPMENT 


147 


and so on. A curious fact is that in each of these orders the sum 
of the numbers of two cylinders which fire in succession is always 5. 
By starting always with a right-hand cylinder, the firing order can 
readily be determined by noting whether the firing order in one of 
the groups of four cylinders is 1- 3- 4-2 or 1- 2- 4- 3. 

Just as the eight-cylinder V-type motor is simply a combination 
of two groups of four cylinders, each of which considered alone 
would have the standard firing order of a four, so the twelve- 
cylinder V-motor is simply the bringing together on one crankshaft of 
two six-cylinder motors. The firing order adopted is aecordingly 
one of the two preferred for the six-cylinder motor (g and h), alter¬ 
nating from the right-hand to the left-hand group in the same 
manner as shown for the eight-cylinder motor. 

Firing Orders and Ignition Advance. Repairs and adjustments 
to the ignition system of a motor are always much easier to earry 
out when the characteristics of the system in question are known. 
For this reason the firing orders of the various models of different 
makes, together with the setting point and the amount of advance 
and retard, are given here for practically all makes of cars. Where- 
ever it could be obtained, this information is given for all models of 
every make for the past five years, but in some instances it was not 
available. The information is given in the alphabetical order of 
the makers’ names to make reference easy. 

Allen 

1917 Fours. Firing order 1- 2- 4- 3. 

Battery ignition; extreme retard, dead center; maximum 

advance 30°. 

Apperson 

1914- 15 Fours. F.O. 1- 3- 4- 2. 

1915- 16-17 Sixes. F.O. 1- 5- 3- 6- 2- 4. 

1916- 17 Eights. F.O. IR- 4L- 3R- 2L- 4R- IL- 2R- 3L. 

Extreme retard, dead center; maximum advance 15°. 

Auburn 

Sixes. Models Six-45, Six-46, and Six-47. 

F.O. 1- 4- 2- 6- 3- 5. 

Models Six-40, Six-40A, Six-44, Six-38, and Six-39. 

F.O. 1- 5- 3- 6- 2- 4. 

Most of the above models are equipped with battery ignition. 


148 


ELECTRICAL EQUIPMENT 


Austin 

Twelves. F.O. IR- IL- 4R- 4L- 3R- 3L- 6R- 6L- 2R- 2L- 5R- 5L. 
Delco system. 

Biddle 

Fours. F.O. 1- 3- 4- 2. 

Magneto setting; full retard, upper dead center. 

Bour=Davis 

Sixes. F.O. 1- 5- 3- 6- 2- 4. 

Brewster 

Fours. F.O. 1- 3- 4- 2. 

Magneto setting; maximum advance when piston is 5 mm. 
(practically i inch) below upper dead center. 

Briscoe 

Fours. F.O. 1- 3- 4- 2. 

Eights. F.O. IR- IL- 3R- 3L- 4R- 4L- 2R- 2L. 

Ignition setting; upper dead center; maximum advance 15°. 

Buick 

1913 Fours. F.O. 1- 3- 4- 2. 

Remy Model, RL magneto; extreme retard, dead center; 
maximum advance about 30°. 

1914-16 Fours. F.O. 1- 3- 4- 2. 

Sixes. F.O. 1- 4- 2- 6- 3- 5. 

All models since 1913 Delco battery-ignition system; extreme 
retard, 7° beyond dead center, except on Alodels B-24-5 and 
36-7, on which 40° retard is provided, owing to the excessive 
amount of advance provided in the distributor assembly; 
maximum hand advance 50° to 72°. Models D-44-5, 
D-54-55, C-54-55, 15° automatic advance. Models C-36-37 
and C-4, automatic advance 24° 32'. 

Case 

1914-15-16-17 Fours. F.O. 1- 3- 4- 2. 

Extreme retard, dead center; maximum advance 30°. 
Cliadwick 

Sixes. F.O. 1- 3- 2- 6- 4- 5. 

Chalmers 

1912-13-14 Fours. F.O. 1- 3- 4- 2. 

Magneto setting; extreme retard, dead center; advance not 
given. 


ELECTRICAL EQUIPMENT 149 

1914 Sixes. F.O. 1- 4- 2- 6- 3- 5. 

Magneto setting; extreme retard, dead center; advance li 
inches on flywheel. 

1915 Sixes. F.O. 1- 4- 2- 6- 3- 5. 

Atwater Kent battery system; extreme retard, 1| inches on 
flywheel. 

1915 Sixes. F.O. 1- 4- 2- 6- 3- 5. 

Magneto setting; extreme retard, dead center. 

191G Sixes. F.O. 1- 4- 2- 6- 3- 5. 

Atwater Kent battery system; extreme retard, dead center. 

1916 Sixes. Model 35. F.O. 1- 4- 2- 6- 3- 5. 

Remy magneto setting; extreme retard, dead center. 

Chandler 

All Models. F.O. 1- 5- 3- 6- 2- 4. 

Magneto; extreme retard; interrupter opens at top dead 
center; this is when back edge of magneto armature is central 
between pole pieces; maximum advance 30° to 35° at the 
magneto or 20° to 25° at the crankshaft. 

Chevrolet 

1912-17 Fours. F.O. 1- 2- 4- 3. 

Sixes. F.O. 1- 4- 2- 6- 3- 5. 

Eights. F.O. IL- 3R- 2L- IR- 4L- 2R- 3L- 4R. 

Chicago 

Sixes. F.O. 1- 5- 3- 6- 2- 4. 

Battery ignition setting; extreme retard, upper dead center. 

Coey 

Fours. F.O. 1- 3- 4- 2. 

Sixes. F.O. 1- 4- 2- 6- 3- 5. 

Cole 

1912-14-15 Sixes. F.O. 1- 5- 3- 6- 2- 4. 

1912-13 Fours. F.O. 1- 3- 4- 2. 

1916-17 Eights. F.O. 1- 8- 3- 6- 4- 5-2-7. 

Battery ignition on all later models. 

De Dion 

Fours. F.O. 1- 3- 4- 2. 

Eights. IR- 4L- 3R- 2L- 4R- IL- 2R- 3L. 

Magneto fixed ignition; setting point, 6 to 10 mm. before 
upper dead center. 


150 


ELECTRICAL EQUIPMENT 


Dixie 

Four. F.O. 1- 3- 4- 2. 

Dodge 

All Models. F.O. 1- 3- 4- 2. 

Eisemann magneto; setting point at extreme retard, 5° in 
advance top dead center; maximum advance 30°. 

Dorris 

Fours. F.O. 1- 3- 4- 2. 

Magneto set to fire at upper dead center when fully retarded. 
Sixes. F.O. 1“ 5- 3- 6- 2- 4. 

Same setting; maximum advance 35°. 

Dort 

All Models. F.O. 1- 3- 4- 2. 

Battery ignition system. 

Elkhart 

Fours. F.O. 1- 3- 4- 2. 

Empire 

Model 31. F.O. 1-2-4-3. 

On motors with chain-driven camshaft. Magneto; fixed 
ignition point 17° in advance of dead center. 

Model 31. F.O. 2-1-3-4. 

On motors having a gear-driven camshaft. 

Models 33 and 31-40. F.O. 1- 2- 4- 3. 

Battery ignition with Remy distributor; extreme retard, 
upper dead center. 

Models 40, 45, and 50. F.O. 2- 1- 3- 4. 

Battery ignition. 

Models 60 and 70. F.O. 1- 5- 3- 6- 2- 4. 

Battery ignition; extreme retard, upper dead center. 

Enger 

Sixes. F.O. 1- 5- 3- 6- 2- 4. 

Twelves. F.O. IR- IL- 5R- 5L- 3R- 3L- 6R- 6L- 2R- 2L- 4R- 2L. 
Battery ignition. It will be noted that this is exactly the 
same as the firing order of the sixes, except that the order 
alternates from one group to the other; this is true of most 
eight-cylinder and twelve-cylinder motors; that is, the 
firing order is equivalent to that of two alternate fours 


or sixes. 


ELECTRICAL EQUIPMENT 


151 


Erie 

Fours. F.O. 1- 2- 4- 3. 

Fiat 

Fours. F.O. 1- 3- 4- 2. 

Sixes. F.O. 1- 4- 2- 6- 3- 5. 

Ford 

Fours. All Fours since 1906. F.O. 1- 2- 4- 3. 

Sixes. Built about 1905 or 1906. F.O. 1- 2- 3- 6- 5- 4. 

The Ford magneto is not timed to the engine; owing to the 
large number of poles and armature coils, it delivers a con¬ 
stant current (alternating) which is timed by the commuta¬ 
tor, or timer, in the same manner as with a battery source 
of supply. 

Franklin 

Sixes. F.O. 1- 4- 2- 6- 3- 5. 

Magneto setting point measured on rim of flywheel, li 
inches for Franklin series 5, 6, 7, and 8 motors; 2J inches 
for series 9 motor. In the series 5-8, inclusive, the flywheel 
is 18 inches in diameter, while in series 9 it is 17 inches. 
Maximum advance series 5-8, 7j inches on flywheel; series 
9, 7 inches. 

F. R. P. 

Fours. F.O. 1- 2- 4- 3. 

Contact points of magneto open when magneto armature is 
I inch from pole piece, piston being at upper dead center. 
This gives spark at approximately dead center, with full 
retard. Advance is maximum afforded by magneto used. 

Glide 

Fours. F.O. 1- 3- 4- 2. 

Sixes. F.O. 1- 5- 3- 6- 2- 4. 

Magneto setting; extreme retard, upper dead center. 

Grant 

Fours. F.O. 1- 2- 4- 3. 

Sixes. F.O. 1- 4- 2- 6- 3- 5. 

Hollier 

Sixes. F.O. 1- 4- 2- 6- 3- 5. 

Eights. F.O. 1-6-3-5-4-7-2-8. 

Battery ignition, Remy system on the six-cylinder model 


152 


ELECTRICAL EQUIPMENT 


and Atwater Kent on the eight-cylinder. Ignition setting; 
extreme retard, upper dead center; maximum advance 
approximately 15°. 

Homer=Laughlin 

1916 Eights. F.O. 1- 8- 3- 6- 4- 5- 2- 7. 

1917 Eights. F.O. 1- 6- 3- 5- 4- 7- 2- 8. 

Magneto setting point approximately 5° after piston passes 
upper dead center; maximum advance about 30°. 

Hudson 

Sixes. F.O. 1- 5- 3- 6- 2- 4. 

The following instructions for ignition setting as applied to the 
Delco ignition system used on the Hudson cars are also applicable, 
with slight modifications, to practically all cars using this system, 
although the amount of advance will naturally differ in many cases. 
First, remove the distributor head and measure the gap between the 
distributor contacts. This should be done when they are opened to 
the maximum. The gap should be set at .012 to .018 inch, using 
the feeler gage on the Delco distributor wrench provided for this 
purpose. Set the spark lever at the top of the quadrant or in the 
fully advanced position; open all the priming cocks. When No. 1 
cylinder blows air out of its priming cock, its piston is rising on the 
compression stroke. 

On Model Six-40, 1914, No. 1 cylinder is due to fire in the 
advanced position when the line A on the flywheel reaches the pointer 
attached to the crankcase. This may be observed through the 
inspection hole on the flywheel housing on the left side of the motor. 
This line A is 2f inches before dead center for cylinders Nos. 1 and 6. 
The 1915-16 Six-40 Models are due to fire on No. 1 cylinder J inch 
before dead center; 1914-16 Model 54, 6 inches before dead center; 
1916 Super Six, f inch before dead center, the setting in each case 
being checked by bringing the line A on the flywheel directly opposite 
the pointer. 

After the piston of No. 1 cylinder has been brought to the proper 
position, loosen the cam on the distributor shaft by turning out the 
set screw in the center of the shaft. Set the distributor so that when 
the contacts are just opening, the button on the rotor comes under 
No. 1 on the distributor head. The spark occurs the instant the 
contacts separate. In checking the timing, the cam should be held 


ELECTRICAL EQUIPMENT 


153 


in tension against its direction of rotation, which is clockwise, so that 
all play, or blacklash, will be taken up. The set screw must always 
be screwed home tight after checking or making an adjustment, to 
prevent its slipping. The rotor should now be replaced on the 
distributor shaft, first rubbing a slight amount of vaseline on the 
rotor track with the finger, and the distributor head put back in 
position tightly. 

Hupp 

Up to 1912. Model 20. F.O. 1- 2- 4- 3. 

Bosch high-tension magneto; fixed firing point. 

Up to 1915. Model 32. F.O. 1- 2- 4- 3. 

Magneto; manual advance. 

Models K and N. F.O. 1-2-4- 3. 

Atwater Kent; manual and automatic spark advance. 
1911-12. F.O. 1-3-4-2. 

Magneto; extreme retard, upper dead center; advance 37i°. 

Interstate 

1915-17. Model T. F.O. 1- 2- 4- 3. 

Magneto setting; extreme retard, upper dead center; maxi¬ 
mum advance 20°. 

1914-15. Model 45. F.O. 1- 5- 3- 6- 2- 4. 

Extreme retard, upper dead center; maximum advance 37i°. 

Jackson 

1917. Model 349. F.O. Rl- LI- R3- L3- R4- L4- R2- L2. 
Jeffery 

1913 Fours. F.O. 1- 2- 4- 3. 

1914 Fours. F.O. 1- 3- 4- 2. 

Advance 35°. 

1915 Fours. F.O. 1- 3- 4- 2. 
x4dvance 35°. 

1915 Sixes. Model 104. F.O. 1- 5- 3- 6- 4- 2. 

Advance 22i°. 

Sixes. Model 106. F.O. 1- 4- 2- 6- 3- 5. 

Advance 22i°. 

1916 Sixes. Model 96. F.O. 1- 4- 2- 6- 3- 5. 

Advance 22i°. 

Sixes. Model 661. F.O. 1- 5- 3- 6- 2- 4. 

Advance 24°. 


154 


ELECTRICAL EQUIPMENT 


Fours. Models 462 and 472. F.O. 1- 3- 4- 2. 

Advance 28°. 

1917 Sixes. F.O. 1- 5- 3- 6- 4- 2. 

Advance 28°. 

Fours. F.O. 1- 3- 4- 2. 

Advance 28°. Magneto setting point all models; spark 
lever full retard, dead center. 

King 

1913- 14 Fours. F.O. 1- 3- 4- 2. 

1915-16 Eights. F.O. IL- 8R- 3L- 6R- 4L- 5R- 2L- 7R. 

Battery ignition; automatic spark advance; extreme retard, 
upper dead center; advance increases automatically with 
speed of motor. 

Kisselkar 

Fours. F.O. 1- 3- 4- 2. 

Sixes. Models Fll, G9, and GIO, 1912-15, Six-60 and Six- 
48. F.O. 1- 4- 2- 6- 3- 5. 

Model Six-42 and Hundred Point Six. F.O. 1-5-3- 6- 2- 4. 

Kline 

Fours. F.O. 1- 2- 4- 3. 

Up to and including 1914 Sixes. F.O. 1- 4- 2- 6- 3- 5. 

1915-17 Sixes. F.O. 1- 5- 3- 6- 2- 4. 

Lexington=Howard 

1908-12 Fours. F.O. 1- 3- 4- 2. 

1914- 15 Fours. F.O. 1- 3- 4- 2. 

1913-14 Sixes. F.O. 1- 5- 3- 6- 2- 4. 

1915- 17 Sixes. F.O. 1- 5- 3- 6- 2- 4. 

Setting point with full retard, dead center. 

Liberty 

Sixes. F.O. 1- 5- 3- 6- 2- 4. 

Distributor set 1 inch late. 

Locomobile 

1910-12 Fours. F.O. 1- 2- 4- 3. 

1913 Sixes. F.O. 1- 5- 3- 6- 2- 4. 

The armature shaft of the magneto is set so that the 
H=shaped core is 14 millimeters, or .551 inch, from the pole 
piece of the magneto for Model 30 and 21 millimeters, or 
.827 inch, for Models 38 and 48. 


ELECTRICAL EQUIPMENT 


155 


1914- 15 Sixes. F.O. 1- 5- 3- 6- 2- 4. 

The armature shaft of the magneto is set so that the 
H=shaped core is 21 millimeters, or .827 inch, from the pole 
piece of the magneto in Model 38 and 25 millimeters, or 
.985 inch, for Model 48. 

1916-17. F.O. 1- 5- 3- 6- 2- 4. 

The magneto is set so that with the spark lever fully ad¬ 
vanced, the spark occurs while the piston is still inch from 
upper dead center on Model 48 and A inch on Model 38. 
McFarlan 

1912 Sixes. F.O. 1- 4- 2- 6- 3- 5. 

Eisemann magneto; interrupter set back of center at full 
retard, i inch. 

1913 Sixes. Teetor motor. F.O. 1- 5- 3- 6- 2- 4. 

Interrupter set back of center at full retard, i inch. 
Herschel motor. F.O. 1- 4- 2- 6- 3- 5. 

Eisemann magneto; interrupter set back of center at full 
retard, 4 inch. 

1914 Sixes. F.O. 1-5-3-6-2-4. 

Mea magneto; interrupter set back of center at full retard, 
i inch. 

1915- 17 Sixes. F.O. 1- 5- 3- 6- 4- 2. 

Westinghouse and Bosch; interrupter set back of center at 
full retard, f inch. The amount of advance provided is 25° 
on the interrupter housing, with the exception of Model 65, 
which has 154° automatic advance and 174° hand advance. 

Madison 

Sixes. F.O. 1- 5- 3- 6- 2- 4. 

Eights. F.O. IR- IL- 3R- 3L- 4R- 4L- 2R- 2L. 

Battery ignition. 

Marion=Handley 

1916- 17 Sixes. F.O. 1- 5- 3- 6- 4- 2. 

Marmon 

Up to 1912 Fours. F.O. 1- 3- 4- 2. 

1913-17 Sixes. F.O. 1- 5- 3- 6- 2- 4. 

Magneto setting point, with spark lever fully retarded, one 
inch past upper dead center, as measured on flywheel; maxi¬ 
mum advance 35°. 


156 ELECTRICAL EQUIPMENT 

Maxwell 

Model 25. F.O. 3-4-2-1. 

Magneto is set to fire, with spark lever at fully retard 
wdien piston has traveled A inch down on firing stroke. 

Mercer 

1913-17 Fours. F.O. 1- 3- 4- 2. 

Magneto setting, with spark lever fully advanced, 1 inch 
before piston reaches upper dead center, or 41° on flywheel. 

Militaire 

Fours. F.O. 1- 3- 4- 2. 

Setting point; extreme retard, upper dead center. 

Mitchell 

Fours. F.O. 1- 3- 4- 2. 

Sixes. F.O. 1- 5- 3- 6- 2- 4. 

1912- 14 Models, inclusive. 

Magneto setting; extreme retard, upper dead center. 

1915- 16 Models, inclusive. 

Battery ignition; setting point, 10° past upper dead center; 
maximum advance 40°. 

Moline 

All Models. Fours. F.O. 1- 3- 4- 2. 

Magneto, set to fire at upper dead center with spark lever 
fully retarded. 

Monroe 

Fours. Model 2. F.O. 1- 2- 4- 3. 

Models, 3-4. F.O. 1- 3- 4- 2. 

Battery ignition. 

Moon 

1916- 17 Sixes. F.O. 1- 5- 3- 6- 2- 4. 

Murray 

Eights. F.O. IR- IL- 3R- 3L- 4R- 4L- 2R- 2L. 

Magneto setting; extreme retard, 1 inch past center line on 
flywheel. 

National 

1913- 16 Sixes. F.O. 1- 5- 3- 6- 2- 4. 

1916-17 Twelves. F.O. 1- 12- 9- 4- 5- 8- 11- 2- 3- 10- 7- 6. 

Magneto setting point, with spark lever fully advanced, 1 
inches on flywheel before piston reaches upper dead center. 


(Mm 


ELECTRICAL EQUIPMENT 


157 


Oakland 

All Four-Cylinder Models. F.O. 1- 3- 4- 2. 

All Sixes. F.O. 1- 5- 3- 6- 2- 4. 

Eights. F.O. 1- 8- 3- 6- 4- 5- 2- 7. 

Maximum advance allowed, 24°. 

Oldsmobile 

Models 42-43. Fours. F.O. 1- 3- 4- 2. 

Delco battery ignition system; maximum advance 80°; 
maximum retard 40°, measured on flywheel, on all models. 

IModel 54. Sixes. F.O. 1- 5- 3- 6- 2- 4. 

Model 44. Eights. F.O. 1- 8- 3- 6- 4- 5- 2- 7. 

Packard 

Up to 1912. Fours. F.O. 1- 2- 4- 3. 

Magneto setting point, with spark lever fully advanced, F| 
inch before piston reaches upper dead center. 

1912-15 Sixes. F.O. 1- 4- 2- 6- 3- 5. 

Magneto setting point, with spark lever fully advanced, ^ 
to i inch before piston reaches upper dead center. 

1916-17 Twelves. F.O. IR- 6L- 4R- 3L- 2R- 5L- 6R- IL- 3R- 
4L- 5R- 2L. 

It will be noted that this firing order is the same in each block of 
six cylinders, beginning with No. 1 in the right block and following 
with No. 6 in the left, as in the six-cylinder model. 

Maximum advance, | inch before piston at upper dead center. 

The variation in the amount of advance allowed is accounted for 
by the difference in speed. The four-cylinder motors were equipped 
with a low-tension magneto having a considerable ignition lag, so 
that a large amount of advance was necessary. The six-cylinder 
motors ran at a higher speed and were equipped with a high-tension 
magneto in which the ignition lag was greatly reduced, so that not 
as much advance was necessary. While the ignition system of the 
twin-six motor has no greater lag than the high-tension magneto 
used on the six-cylinder motor, the speed is so much greater that an 
amount of advance approximately equal to that of the much slower 
four-cylinder motor is necessary. 

Paige=Detroit 

1911-14 Fours. F.O. 1- 3- 4- 2. 

1915-17 Sixes. F.O. 1- 5- 3- 6- 2- 4. 


158 


ELECTRICAL EQUIPMENT 


Pathfinder 

Twelves. F.0.1R- IL- 4R- 4L- 2R- 2L- 6R- 6L- 3R- 3L- 5R- 5L. 
Battery ignition. 

Patterson 

1911-12-13Fours. Models 30,41,43,45, and47. F.0.1-3-4-2. 
1914-15. Model Four-32. F.0. 1- 3- 4- 2. 

1915 Sixes. Model Six-48. F.0. 1- 5- 3- 6- 2- 4. 

1916. Model Six-42. F.0. 1- 5- 3- 6- 2- 4. 

1917. Model Six-45. F.0. 1- 5- 3- 6- 2- 4. 

Magneto settings; extreme retard, dead center, on all models. 

Peerless 

1912 Fours. F.0. 1- 2- 4- 3. 

Sixes. Models J and K. F.0. 1- 3- 2- 6- 4- 5. 

Sixes. Model L. F.0. 1- 4- 2- 6- 3- 5. 

1913-14 Sixes. F.0. 1- 4- 2- 6- 3- 5. 

1915 Sixes. Model 5K. F.0. 1- 4- 2- 6- 3- 5. 

Sixes. Model EE. F.0. 1- 5- 3^ 6- 2- 4. 

Fours. Model DD. F.0. 1- 3- 4- 2. 

1916 Eights. F.0. IR- IL- 3R- 3L- 4R- 4L- 2R- 2L. 

1917 Eights. F.0. IR- 4L- 3R- 2L- 4R- IL- 2R- 3L. 

Model 2J. Full advance is equivalent to 3§ inches before 
dead center, as measured on the flywheel. 

Model 2K, 3f inches before dead center. 

Model 2L, 2J inches before dead center. 

Model 5K, 4 inches before dead center. 

Model TC (commercial motor), 28°, or 4.68 inches, before 
dead center on maximum advance and 7°, or 1.17 inches, 
past dead center on full retard. 

Last 50 Model 2K, 2f inches full advance instead of 3f 
inches. 

Pierce=Arrow 

All Sixes. F.0. 1- 5- 3- 6- 2- 4. 

Model C4. Magneto set to have interrupter contacts open 
when magneto mark on flywheel is directly opposite pointer 
on crankease; battery system; spark occurs when igniter 
mark on flywheel is opposite pointer on crankcase and mark 
indicating cranks of Nos. 1 and 6 cylinders is directly on 
top center. 


ELECTRICAL EQUIPMENT 


159 


Model B4. Magneto set to have interrupter contacts open 
when magneto mark on flywheel registers with pointer and 
mark indicating cranks of Nos. 1 and 6 cylinders is 3 % inch 
over top center; battery system; spark occurs when igniter 
mark on flywheel registers with pointer and mark indicating 
cranks Nos. 1 and 6 cylinders is directly on top center. 
Model A4. Magneto set to have interrupter contacts open 
when magneto mark on flywheel registers with pointer and 
mark indicating cranks Nos. 1 and 6 cylinders is If inches 
over top center; battery system; spark occurs when igniter 
mark on flywheel registers with pointer and mark indicating 
cranks Nos. 1 and 6 cylinders is f inch over top center. 

Pilliod 

Fours. F.O. 1 - 3- 4- 2 . 

Magneto set to give 15° retard and 15° advance. 

Premier 

1916-17 Sixes. F.O. 1 - 5- 3- 6 - 2 - 4. 

With the spark lever fully retarded, the breaker points are 
set to open 2 ° to 3 ° late on flywheel, while the maximum 
advance is 25°. The pistons are not accessible when motor 
is fully assembled. 

Princess 

Fours. F.O. 1- 2 - 4- 3. 

Setting point for magneto, 8 ° past dead center at full retard; 
maximum advance 20 °. 

Pullman 

Fours. F.O. 1- 2 - 4- 3. 

Regal 

All Fours except 1915-16. F.O. 1 - 2 - 4- 3. 

1915- 16 Fours. F.O. 1- 3- 4- 2 . 

1916- 17 Eights. F.O. IR- IL- 3R- 3L- 4R- 4L- 2R- 2L. 

The magneto in earlier models and battery-ignition system 
in later cars set to fire at upper dead center, with spark lever 
in fully retarded position. Remy magneto on 1909-10 cars; 
Michigan magneto 1910-14; Atwater Kent system 1915 
models; Connecticut system 1916 models; and Heinze- 
Springfield starting, lighting, and ignition system 1917 
models. Maximum advance in all cases approximately 30°, 


160 


ELECTRICAL EQUIPMENT 


Reo 

1910-17 Fours. F.O. 1- 3- 4- 2. 

1915-17 Sixes. F.O. 1- 4- 2- 6- 3- 5. 

1910-15, Four-Cylinder Models. Magneto setting, | inch 
before upper dead center, with spark lever in fully retarded 
position; maximum advance 5§ inches. 

1916-17, Four-Cylinder Models. Magneto setting, upper 
dead center; maximum advance 6i inches. 

1915, Six-Cylinder Model. Magneto setting, 1 inch before 
upper dead center; maximum advance 7i inches. 

1916-17, Six-Cylinder Models. Magneto setting, upper 
dead center; maximum advance 8i inches. All measure¬ 
ments are on the periphery of the flywheel; 1 inch on the 
latter is equivalent to 7.10°. 

Ross 

Eights. F.O. IR- 2L- 5R- 6L- 7R- 8L- 3R- 4L. 

Battery ignition. 

Saxon 

Fours. F.O. 1- 3- 4- 2. 

Sixes. F.O. 1- 5- 3- 6- 2- 4. 

Scripps=Booth 

Fours. F.O. 1- 3- 4- 2. 

Eights. F.O. IR- IL- 3R- 3L- 4R- 4L- 2R- 2L. 

Simplex 

Fours. F.O. 1- 3- 4- 2. 

Sixes. F.O. 1- 4- 2- 6- 3- 5. 

Singer 

Sixes. F.O. 1- 4- 2- 6- 3- 5. 

Magneto setting; extreme retard, top dead center. 

Spaulding 

Fours. F.O. 1- 3- 4- 2. 

Models CP and CS, Remy magneto; Model E, Bosch 
magneto; Model G, Eisemann magneto; Models H and I, 
Simms magneto; magneto settings; extreme retard, dead 
center. 

Sphinx 

Fours. F.O. 1- 3- 4- 2. 

Battery ignition. 


ELECTRICAL EQUIPMENT 


161 


Standard 

Eights. F.O. IR- IL- 3R- 3L- 4R- 4L- 2R- 2L. 

Ignition setting point, magneto contacts just opening with 
piston 2 inches (on flywheel) past dead center, at full retard; 
maximum advance 25°. 

Stearns 

1912- 14 Fours. F.O. 1- 2- 4- 3. 

1915- 17 Fours. F.O. 1- 3- 4- 2. 

1913- 15 Sixes. F.O. 1- 5- 3- 6- 2- 4. 

1916- 17 Eights. F.O. IR- 8L- 3R- 6L- 4R- 5L- 2R- 7L. 

All the above have the Knight motor. 

1915-17. Magneto setting, with the spark lever fully 
retarded, is 1J inches past dead center, as measured on the 
flywheel. 

On all other models, the magneto setting point is upper 
dead center; maximum advance in all cases is approxi¬ 
mately 30°. 

Studebaker 

Model 20. Fours. F.O. 1- 2- 4- 3. 

All Other Fours. F.O. 1- 3- 4- 2. 

All Sixes. F.O. 1- 5- 3- 6- 2- 4. 

All Four-Cylinder Models. Ignition setting point is 4 inches 
before upper dead center, as measured on the flywheel. 
All Six-Cylinder Models. Ignition setting point is 5| 
inches before upper dead center, as measured on the 
flywheel. 

Stutz 

All Four-Cylinder Models. F.O. 1- 3- 4- 2. 

All Six-Cylinder Models. F.O. 1- 4- 2- 6- 3- 5. 

Sun 

Sixes. F.O. 1- 4- 2- 6- 3- 5. 

Thomas 

Sixes. F.O. 1- 4- 2- 6- 3- 5. 

Ignition setting point, magneto contacts opening J inch on 
travel of piston before upper dead center at full advance. 

Trumbull 

Fours. F.O. 1- 3- 4- 2. 

Fixed ignition setting. 


162 


ELECTRICAL EQUIPMENT 


Velie 

1916-17 Sixes. F.O. 1- 5- 3- 6- 2- 4. 

Ignition setting point, upper dead center with spark lever 

fully retarded. 

Westcott 

1910-14 Fours. F.O. 1- 3- 4- 2. 

1913-17 Sixes. F.O. 1- 5- 3- 6- 2- 4. 

1910-14. Remy and Bosch magnetos; ignition setting 

point, upper dead center. 

1914 Fours. Atwater Kent system, upper dead center. 

1913 Sixes. Bosch magneto; ignition setting point, with 
spark lever fully retarded, 1| inches late, or past dead center. 

1915 and later Sixes. Delco ignition. 

Willys=Overland 

All Four-Cylinder Models. F.O. 1- 3- 4- 2. 

All Six-Cylinder Models. F.O. 1- 5- 3- 6- 2- 4. 

Magneto setting point, with spark lever fully retarded, f 
inch to li inches late, or past dead center; maximum 
advance 30° to 35°. 

Winton 

Since 1907. Sixes. F.O. 1- 5- 3- 6- 2- 4. 

Magneto setting point with spark lever fully retarded, upper 
dead center. 

Wiring. Necessity for High-Tension Cables. Mention has been 
made of the fact that in early days much trouble was experienced 
with poorly insulated and poorly mounted wires. This was par¬ 
ticularly the case with the secondary circuits, the insulation of which 
was frequently inadequate to carry currents at the high potentials 
employed, so that there was more or less leakage. This was further 
aggravated by the chafing, or rubbing, of these wires against moving 
parts. The former trouble was eliminated by the adoption of 
specially constructed cables which are tested to carry 30,000 volts. 
Cables of this type are illustrated in Fig. Ill, which also shows the 
cables employed for electric lighting and starting installations, where 
the chief difficulty has usually been the selection of a cable of too 
small a carrying capacity for the current used. 

The importance of using heavily insulated cables for both the 
primary and secondary cables of the ignition, and, more particularly 


ELECTRICAL EQUIPMENT 


163 


the latter, has come to be generally understood, and cables especially 
designed for this service have now been in use for a number of years; 
but the importance of using wiring of ample capacity, in the lighting 
and starting circuits, is not so well appreciated. In the former 
instance, the problem was one of insulation only, the amount neces¬ 
sary to prevent leakage of the secondary current not being fully 
realized in the early days; nor was the necessity for thoroughly pro¬ 
tecting the primary cables from the effects of oil and water taken into 
account. Trouble from these sources, however, have long since been a 
matter of the past; even the well-insulated cables now in general 



Combination High Tension Cable 



Fig. 111. Types of Cables Employed in Electrical Equipment of Automobiles 

use become oil soaked in time, but, when faulty ignition is thought to 
be due to them, they are promptly replaced. 

In many of the early electric starting and lighting systems, the 
wiring has been as poorly adapted to the purpose as was that of the 
pioneer ignition systems. This was not on account of improper insu¬ 
lation but owing rather to poor design or to a lack of consideration 
of the importance that proper wiring has on the efficient operation 
of the system. No electrical system of this kind is any better than 
its storage battery; and, as the amount of energy that can be hus¬ 
banded in the latter is limited, every effort must be made to avoid 
waste in its use. What constitutes waste in a standard lighting 
system using current at 110 to 115 volts, and what may be so termed 




164 


ELECTRICAL EQUIPMENT 


where the available potential is only 6 volts, are two very different 
things. A voltage drop of one to 5 volts in an incandescent lighting 
system is negligible. A drop of 5 volts below the 110-volt standard 
will cause a perceptible dimming of the lamps, but the life of the lamp 
filaments themselves will be greatly increased, other factors remaining 
the same, so that the loss in efficiency is not of such great moment. 

Importance of Voltage Drop. But, in an electric starting and 
lighting system, the loss of even a fraction of a volt due to the wiring 
represents a substantial falling off in the power. As mentioned in the 
introductory, the unit of potential, or voltage, times the unit of 
current flow, or ampere, equals the watt or power unit, and there are 
746 watts in an electrical horsepower. Take the case of an electric¬ 
starting motor with an unusually long connection between the battery 
and the electric motor. Assuming that the length and diameter of 
this wire is such that there is a loss of 1 volt between the battery 
and the motor and that, at the moment of starting, 300 amperes are 
required to break away the engine, i.e., free the pistons and bearings 
when the lubricating oil has thickened from the cold so as to bind 
them. In the actual power consumed, this voltage drop represents 
300 X1, or 300 watts, equivalent to more than f horsepower. 

The loss of but J volt, other factors remaining the same, is equiva¬ 
lent to almost I horsepower, or about what a strong man can exert 
for a limited time. This appears to be getting things down pretty 
fine, but in the case of the Dyneto system, the manufacturers specify 
that the cable between the starting motor and the storage battery 
must be large enough to transmit 400 amperes with a total loss not to 
exceed J volt. With this amount of current, the voltage drop in 
question represents 100 watts, or nearly y horsepower. Of course, 
this loss only takes place at the instant of starting, but that is just 
the time when the highest efficiency and the full power of the battery 
is required. Moreover, the starting motor frequently has to be oper¬ 
ated a number of times, especially in cold weather when the battery 
efficiency is at its lowest, before the engine will start. Even at the 
lower-current values necessary for turning the engine over after it has 
been broken away, a drop of one volt represents an appreciable power 
loss, as the current consumed is anywhere from 50 to 100 amperes. 
It will be apparent from this why the manufacturers lay such empha¬ 
sis on their instructions not to lengthen connections, if avoidable. 


ELECTRICAL EQUIPMENT 


165 


and then only to use wire of the same size and kind. This, of course, 
does not apply to the starting motor connection, as that should 
never be lengthened without increasing the diameter of the wire to 
compensate for the increase in length. 

Calculating Size of Cable. It is not advisable to do so where it 
can possibly be avoided, but, when made necessary by the fitting of an 
enclosed body, the following formula should be used for calculating 
the size of cable that should be employed: 


Maximum current X 10.7 X number of feet of wire 

.25 


= diameter or cross- 


section of wire in circular mils 


For example, in the case cited above, where the maximum current 
at the instant of starting is 300 amperes and the distance between the 
battery and the starting motor is four feet (measured from battery 
to switch and from the latter to the starting-motor terminal), the 
size of wire necessary would be: 


300X10.7X4 

.25 


= 48,960 circular mils 


As shown in the table on page 27, which gives the corresponding 
sizes of the B & S gage, the nearest to this is No. 3 wire of 52,634 
circular mils cross-section, but, to allow for a factor of safety, either 
a No. 2 or a No. 1 wire would be used for such an installation. Now, 
in case it becomes necessary to take the battery from the running 
board close to the engine and place it under the floor of an enclosed 
body, increasing the length of wire needed to 8 feet, the cross-section 
of the wire required would be 98,720 circular mils, the closest gage 
number to this being the No. 0 cable. In other words, doubling 
the length of the cable would make it necessary to double its cross- 
section in order to prevent exceeding the minimum permissible drop 
in the voltage. This will make plain why some of the amateur 
experiments in re-locating the essentials of an electric starting system 
have had such disastrous effects on its efficiency. 

Effect on Lights. In the case of the lamps, the effect of an 
increased drop in the voltage is not so serious; though, because of the 
very low-battery voltage available, what would otherwise be a 




166 


ELECTRICAL EQUIPMENT 


negligible loss assumes important proportions. On the 3-cell 6-volt 
battery now so generally used, the lamp filaments are designed to 
burn to full brightness on a potential of 6 to 8 volts, this variation 
being provided to compensate for the difference in the battery voltage 
when fully charged and when partly discharged, as the voltage of the 
battery decreases as it discharges, dropping to but 1.50 volts per cell 
when practically exhausted, or a total of 4| volts. Even if receiving 
this full voltage, the 6-volt bulbs would burn very dimly, but there 
must be deducted from it the voltage drop due to the wiring and'the 
switches. This is the reason why the brightness of the lamps (with 
the generator idle) affords such an excellent indication of the state 
of charge of the battery. 

It will be apparent from the above that a drop in potential of but 
one volt in the lighting circuit would cause a serious loss of efficiency 
at the bulbs. Assuming that the headlights consume 4 to 5 amperes, 
and applying the above formula on the basis of a maximum distance 
of 10 feet from the battery, it is found that a No. 16 wire is necessary; 
but, in order to provide a large factor of safety, nothing smaller than 
No. 14 wire is ordinarily employed for the lighting circuits, and, in 
some cases, it is No. 12. 

Importance of Good Connections. Under the head of “Resist¬ 
ance”, however, attention has been called to the fact that not alone 
the length and size of the connecting wires, but also all switches and 
joints are factors in calculating the total resistance of a circuit. 
Consequently, it is poor practice ever to make a joint in a wire where 
a single length may be employed. Whenever a wire is broken by 
accident, the trouble should always be remedied by replacing it with 
an entirely new piece rather than by making a joint in the old wire. 
Loose connections also add greatly to the total resistance in a circuit, 
as well as connections in which the contact faces of the terminals are 
dirty or corroded. In replacing or tightening connections, care should 
be taken to see that the parts in contact are scraped or filed bright 
and that both the terminal nut and its lock nut are screwed down 
firmly. The switches are also an important factor where voltage 
drop is concerned and switch blades or contacts that are dirty or 
corroded, or that are not held firmly in contact when closed, will 
be responsible for an appreciable drop in the voltage that will become 
increasingly perceptible as the battery becomes discharged. 


ELECTRICAL EQUIPMENT 


167 


Magneto Mounting. As the magneto is timed exactly with 
the motor, it must be positively driven synchronously with it at a 
speed depending upon the number of cylinders. This is crankshaft 
speed on a four-cylinder and one and one-half times crankshaft speed 
on a six. It has become standard practice to a very large extent both 
here and abroad to mount the magneto on a “pad” or shelf attached 
to the crankcase and drive it from a special auxiliary shaft, usually 
also utilized for driving the water pump or other motor auxiliary. 
\ ariations from this are to be found in the Renault and a few other 
European as well as American cars, in which the magneto is mounted 



Fig. 112. Mounting of Magneto on Lozier Car 


at the forward end of the motor and driven by a cross-shaft and helical 
gears directly from the crankshaft of the motor. The only advantage 
of this is slightly greater accessibility. In any case, the magneto is 
not permanently fastened but is simply held on its support, against 
movement, by dowel pins in the base and a strap clamp tightened with 
a thumb nut, as shown in Fig. 112, which may be regarded as typical 
of American practice. As the efficiency of the magneto depends to a 
considerable extent on the very limited clearance between its arma¬ 
ture and the pole pieces of the field, usually termed the armature 
tunnel, precautions are taken to avoid placing any stress on it that 
could tend to disturb this accurate alignment. The driving shaft 
is accordingly provided with a universal joint, the long familiar 
Oldham coupling being much used in this country for the purpose. 
On the Pierce-Arrow a leather disc universal drives the magneto and 
also cushions the armature. 










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ELECTRICAL EQUIPMENT FOR 

GASOLINE CARS 

PART III 


IGNITION —(Continued) 

MODERN BATTERY IGNITION SYSTEMS 

Effect of Starting and Lighting Developments on Ignition. 

Prior to the advent of the electrical starting and lighting systems, 
the magneto had reached a degree of development that appeared to 
leave not the slightest doubt as to its representing the ultimate type 
of ignition current generator. With the installation of a direct- 
current generator capable 
of supplying more than 
enough current for light¬ 
ing and starting the car 
and charging a storage 
battery of high capacity, 
however, it appeared that 
there was a duplication 
of electrical apparatus 
for which there was no 
good economic reason. 

In other words, with such 
an ample and reliable 
source of current on the 
car as that presented by 
the charging generator 
and storage battery, why continue the magneto? There is no sound 
reason why one electrical system should not combine all three functions 
of ignition, lighting, and starting, and this has been successfully carried 
out on the Cadillac for several years past, while the Reo and other 
makes have more recently followed suit. 

Generator Design Follows Magneto Precedent. Several gen¬ 
erator designs, have been developed which resemble that of a 
magneto. In the Westinghouse generator, Fig. 113, and the Remy, 



Fig. 113. Westinghou.se Generator with Ignition 
Distributor 







170 


ELECTRICAL EQUIPMENT 


Fig. 114, their contact breakers are of the magneto type, as will be 
plain from the Ilemy, Fig. 62, and the Westinghouse, Fig. 115, to 
cite but two examples of a number. In the case of the Westinghouse, 
the objection previously held against battery ignition—that it 



Fig. 114. Remy Combination Lighting and 
Ignition Generator 


required much more manipulation of the spark advance lever to 
obtain efficient motor running—has been overcome by the provision 
of a centrifugally operated automatic advance device. Fig. 115, simi¬ 
lar in principle and results to the Eisemann and Llerz devices, Figs. 



Fig. 115. Westinghouse Contact Breaker with Automatic 

Spark Advance 


102 and 105, though differing from them in construction. The 
distributors employed are practically identical with those used on 
magnetos, but all resemblance disappears when the machine is 
dismantled. Fig. 116, revealing a compact direct-current generator. 










ELECTRICAL EQUIPMENT 


171 



Fig. 116. Details Westinghouse Lighting and Ignition Generator 


TYPICAL ARRANGEMENTS 

Westinghouse Ignition Unit. This is a combination of all the 
essentials of magnetic ignition, i.e., the interrupter, distributor, 
induction coil, and condenser, brought together in a compact unit 
adapted for mounting either on the lighting generator itself or 
directly on the engine. It supersedes the type of ignition and 
lighting generator previously described and which now will be found 
only on cars of earlier models. As will be noted in Fig. 117, its 
components are the counterparts of the same essentials on the 
magneto, except that the interrupter cam has four lobes, so that no 
further description is necessary. 

Fig. 118 is a wiring diagram of the connections. The interrupter 
and condenser are located at the bottom of the housing with the 



Fig. 117. Details of Westinghouse Ignition Unit 
Courtesy of Westinghouse Electric and Manufacturing Company, East Pittsburgh, Pennsylvania 


induction coil above and the distributor at the top. To prevent an 
excessive amount of current passing through the ignition unit, a 












172 


ELECTRICAL EQUIPMENT 


“ballast resistor” is connected in series with it. This is a resistance 
unit which, in the various models, is combined either with the switch 
or with the fuse box, or may be mounted independently. In case 
this resistance unit should become inoperative for any reason, the 
car may be run by replacing it with a standard 5-ampere fuse cart¬ 
ridge. A fuse of larger capacity than this should not be used and 
the car should not be run any longer than absolutely necessary with 

the fuse in place, as the in¬ 
terrupter contacts would be 
badly burned. The working 
of the interrupter contacts 
may be inspected by loosen¬ 
ing the set screw at the 
bottom of the housing and 
lifting the distributor an inch 
or so. Fig. 119. 

Atwater=Kent System. 
The Atwater-Kent system is 
based on a “single spark” 
interrupter and was the 
pioneer in making battery 
ignition successful on the 
modern automobile before 
the advent of the perfected 
lighting generator, the current 
source usually being a dry-cell 
battery. It was considered 
an advantage in earlier years 
to produce a series of high- 
tension sparks in the cylinder 
on the theory that, if the 
first failed to explode the charge, it would be fired by the subsequent 
sparks. The fallacy of this long since became apparent and the 
reason therefor has been dwelt upon already. The Atwater-Kent 
interrupter is typical of devices of this class which have been 
developed since and as it is fitted on thousands of cars which come 
to the repair man’s attention at one time or another, a detailed 
description of its working is given here. 





To Spark Plugs 
Distributer Brushes 
Induction Coil 


To Ignition Unit 


Condenser ignition Switch 


Ignition 

Switch 




Fuse Box 


Battery 


From Battery 


Fig. 118. Wiring Diagram for Vertical Ignition 
Unit. Left—with Ballast on Rear of 
Ignition Switch; Right—with 
Ballast in Fuse Box 























































































ELECTRICAL EQUIPMENT 


173 


Operation of ‘‘UnisparJier”. The ratchet A, Fig. 120, has as many 
notches as there are cylinders to be fired. It is mounted on the 
central vertical shaft of the device which also carries a distributor, 
and in this combined form is known as a ^‘Unisparker’h On four¬ 
cycle engines it is driven at half crankshaft speed, and at crankshaft 
speed on two-cycle engines (motor boats). The ratchet A engages 
the lifter B, and, as A rotates, its teeth or notches successively tend 
to draw B with them, against the tension of the spring C. In doing 



Ignition Terainals 


Switch 

Terminal 


Inrerrtjpfer Cover 


Interrupter Contacts 


Fig. 119. Westinghouse Ignition Unit with Interrupter 
Cover Raised Showing Interrupter Contacts 

Courtesy of Westinghouse Electric and Manufacturing 
Company, East Pittsburgh, Pennsylvania 


SO, the head of B strikes the swinging lever or “hammer” D, whose 
motion in both directions is limited as shown, and the hammer 
communicates the blow to the contact spring E, bringing the con¬ 
tact points together momentarily. E is a compound spring, the 
straight member of which carries the movable contact, while the 
stationary contact E is mounted opposite it. The second member 
of this compound spring is curved at its end to engage the straight 
member. Ordinarily the straight spring blade is held under the 
tension of the curved blade and the contact points are held apart. 



















174 


ELECTRICAL EQUIPMENT 


When the curved blade is struck by the hammer D the points con¬ 
tact. The curved blade, however, is thrown over farther by the 
impact and its hook leaves the straight blade. Upon reaching the 



Fig. 120. Diagram Showing Operation of Atwater-Kent Interrupter 
Courtesy of “The Horseless Age” 


limit of its movement it flies back and strikes the end of the straight 
blade a blow causing a very sharp break of the circuit. This move¬ 
ment is so extremely rapid that it cannot be detected by the unaided 
eye, so that its working cannot be tested simply by watching the 




















ELECTRICAL EQUIPMENT 


175 


operation of the contacts as in the case of a magneto interrupter. 
By C, and D, of Fig. 120, show the successive movements of the parts 
during a single phase. In .d, a notch of the ratchet has engaged B 
and is drawing it against the tension of the spring C. In the second 
sketch B, the hook is released. In C, the lifter is riding back over 
the rounded portion of the ratchet and striking the hammer D, 
which in turn pushes E for a brief instant against F, The return of 
B to the position shown in sketch D is so rapid that the eye cannot 
follow the movement of the parts D and E, which to all appearances 
remain stationary. 

Adjustment of the contact points is made by removing one of 
the thin washers from under the head of the contact screw F, and 
the gap should be .010 to .012 inch, never exceeding the latter. 
Where more accurate means of 
determining this distance are not 
available, it may be gaged with a 
piece of manila wrapping paper 
which should be perfectly smooth. 

With the aid of a ^^mike” (microm¬ 
eter) a sheet of paper of the proper 
thickness can be selected. The con¬ 
tacts are of tungsten and as the 
moving parts are all of glass-hard 
steel, very accurately machined, 
the wear is negligible so that adjust¬ 
ment is not required oftener than once in 10,000 miles running 
and replacement only after 50,000 miles. 

With this interrupter it is impossible to run the battery down 
by leaving the switch closed inadvertently, as the contacts are 
never together when the moving parts are idle. The remainder of 
the system comprises an induction coil (nonvibrator) and a high- 
tension distributor. 

Connecticut Battery System. While this system also employs 
a single-spark interrupter, it is what is known as a ‘^magneto type”, 
and the similarity to those employed on magnetos for the same 
purpose will be noted in Fig. 121. A characteristic of this type of 
interrupter is that its contacts normally remain closed so that if 
the ignition switch is left on, the battery will be run down. To 



Fig. 121. Connecticut Interrupter 



176 


ELECTRICAL EQUIPMENT 




prevent this in the Connecticut system, an automatic switch acting 
on the thermoelectric principle is employed. The interrupter con¬ 
sists of a semicircular 
arm of sheet steel to make 
it light. This is pivoted 
at one end, carries a roller 
at its center and the 
movable contact at the 
other end. It is insulated 
from its pivot and the 
roller is of fiber. The 
vertical binding post is 
electrically connected 
with the stationary con¬ 
tact and the second one, 
at an angle, connects 
with the movable contact. 
While an interrupter of this type has practically no lag, means of 
advancing the moment of ignition are provided (lever extension at 
left), as the spark must occur earlier at high engine speeds to permit 

of propagating the flame 


Fig. 122. 


Connecticut Igniter Complete Except 
for Switch 


Courtesy of Connecticut Telephone and Electric 
Company, Meriden, Connecticut 


ADJUSTMENT 
l/ SCREW 


throughout the charge in the 
extremely short time avail¬ 
able in the modern high¬ 
speed engine. As the con¬ 
tacts are opened only 
momentarily, the interrupter 
is in circuit most of the time 
and accordingly is not eco¬ 
nomical of current, so that it 
is designed only for use with 
the battery and generator 
of the lighting and starting 
system. 

Fig. 122, shows the com¬ 
plete Connecticut system 
(minus the switch) as designed for mounting on a magneto bed plate. 
The distributor is mounted over the interrupter, while the coil is at the 


Fig. 123. Connecticut Automatic Switch 





ELECTRICAL EQUIPMENT 


177 




i: 


Fig. 124. Wiring Diagram for Connecticut Ignition System 









































































178 


ELECTRICAL EQUIPMENT 


right. The primary of the coil is not grounded, insulated leads 
being connected to the two binding posts of the interrupter, as 
shown. The grounding of the secondary winding of the coil is 
effected through the metal holding band and the bolts fastened to 
the bed plate. A glass tube is employed to house the safety gap 
which is mounted under the cover of the coil. 

Automatic Sivitch. The purpose of the automatic switch. Fig. 
123, is to open the circuit in case the switch button has been left on 
with the car stopped. The current passing with the contacts closed, 
when the engine is idle, is much greater than when it is constantly 
being interrupted by the rapid-fire action of the cam, but, unlike a 
circuit-breaker, the device is not designed to act instantly upon the 
passing of an overload current as this would prevent cranking the 
motor. The device consists of a thermostatic arm regulated by 
the adjustment screw at the top of the figure, an electromagnetic 
vibrator the armature of which carries a hammer, and the necessary 
connections. Current enters at either the right- or left-hand screw 
at the bottom, according to whether the switch is closed at the end of 
the sectors at the right or left of the figure {M or B on the switch 
cover plate), and flows through the heater tape on the arm of the 
thermostat to the screw at the upper right in the figure. This 
heater tape is a resistance that becomes warm upon the passage of' 
a certain amount of current for a short time and, with an increase 
in temperature, causes the arm of the thermostat to bend until 
it makes contact with the upper thermostatic arm. This puts 
the windings of the magnet in circuit through the post just below 
the magnet coils and sets the vibrator in motion, causing the 
hammer on the armature to strike the switch button and open it. 
Fig. 124 is a typical wiring diagram in connection with the lighting 
system, the automatic switch being combined with the lighting 
switch. 

Remy System. The relation that the various essentials of a 
battery-ignition system of the types here described bear to each 
other is made clear by glancing at the graphic wiring diagram of 
the Remy system. Fig. 125. The starting switch shown at the left 
has, of course, no connection with the ignition system but is included 
in the illustration because the current-supply wire for the latter is 
connected to one terminal of the starting switch instead of being 


ELECTRICAL EQUIPMENT 


179 


taken directly to the battery. This is done simply to save wire. 
The source of current supply is the storage, and, as is the case with 
all one-wire systems, one side of the battery is grounded, as shown. 
Similar ground connections, necessary to complete the circuit, will 
be noted at the various units of the system. The colors mentioned 
in connection with the various wires are those of their insulation, 
which serves to identify them. 

Detecting Grounds. All current used by the ignition system 
passes through the ammeter, which thus serves as a method of de¬ 
tecting grounds. For example, if, with the engine idle and all lamps 



/?ed " /d Dup/ex IV/re 

J!/nmeter 


7b 3parA P/ug^ 


PI I grounded fastening5 
mafe ca/rnec!ion ftirough 
frame of car serein g pur¬ 
pose of an extra mre. 


Ground to frame 


JP/stn'hufer 




ti/gh 
Tension 



^se of coil must 
be weirgrounded. 


Fig. 125. Essentials of Battery Ignition System 


turned off, the ammeter registers a discharge, it indicates a leak in 
the system. By disconnecting the wires leading to the lamps, relay, 
and ignition switch in turn, the particular part of the system in which 
the fault lies may be detected. If, for instance, the ammeter needle 
immediately drops back to zero upon disconnecting the lead to the 
ignition switch, it indicates that the leak is in some part of the 
ignition system; if it still indicates a discharge after disconnecting 
this lead, it shows that the leak is in one or the other of the two re¬ 
maining parts of the system to which the wires in question lead, 
and it may be found by continuing the process of elimination further. 
Should the ammeter still show a discharge reading after disconnecting 












































180 


ELECTRICAL EQUIPMENT 


all three of these wires, the trouble would lie either in the starting 
switch or in the cable connecting it with the battery. This could be 
proved by disconnecting the switch from the battery and running an 
independent lead from the battery to the ammeter, temporarily. 
There is always a possibility, of course, that the fault may lie in the 
ammeter itself. A current-measuring instrument is necessarily of 
delicate construction and is apt to suffer from the vibration and jolt¬ 
ing. Before carrying out all the above tests, make certain that 
the ammeter needle has not become stuck. 

Ignition Switch. From the ammeter. Fig. 125, the current passes 
to the ignition switch of the reversing type, that is, it serves to 
change the direction in which the current flows every time it is turned 
on. For the purposes of either ignition or lighting, it is immaterial 
in which direction the current flows, but the latter has an important 
bearing on the life of the expensive contact points in the interrupter. 
As has been explained previously, the passage of a current through 
contact points or across a gap tends to transfer the material of the 
positive electrode to the negative, resulting in the formation of a 
cone at the positive and a crater, or hollow, at the negative. When 
the points have worn to this condition through long service, the 
contact is poor and uncertain, while the points are apt to stick, and 
to put them in good working order means filing away some of the 
platinum which is more costly than gold. The use of a reversing 
switch, which alternately makes the same point positive and negative, 
keeps both contacts in better condition for a greater length of time. 

One side of the ignition switch is grounded on the oiler, through 
which the current passes to the frame to which the oiler or its support 
is attached. This particular connection is merely a matter of con¬ 
venience and is only another instance of saving wire. The wiring 
diagram in question shows the installation of the Remy system on 
the Scripps-Booth four-cylinder chassis; on other machines, the 
ground connection will usually be found in some equally convenient 
point close to the switch. The two remaining connections from the 
ignition switch run to the coil and the interrupter, or contact breaker, 
respectively, and complete the primary circuit. 

Interrupter and Distributor. The interrupter is enclosed in the 
same housing as the distributor. Fig. 125, and is directly below it. 
As with a magneto, the coil is grounded by attaching it to its pedestal 


ELECTRICAL EQUIPMENT 


181 


on the car, the plate shown serving as a ground connection for one 
side of both the primary and the secondary windings of the coil. 
Consequently, but one connection for the primary circuit and one 
for the secondary circuit need be made from the coil to the interrupter. 

By tracing the connections just described, it will be plain that 
when the contacts of the interrupter are closed, current flows from 
the battery through the primary of the coil. The revolving members 
of both the interrupter and the distributor are mounted on a vertical 
shaft driven by helical gearing from one of the half-time shafts of 
the engine. When the cam on this shaft opens the contact points 


C N n 



Mdvanoe. 

Fig. 126. Delco Magneto Type Interrupter 


of the interrupter, the primary circuit is suddenly broken, and a 
high-tension current is induced in the secondary winding of the coil. 
As the revolving member of the distributor is timed to make contact 
with one of its stationary segments every time the contacts of the 
interrupter open, the secondary current is led to one of the spark 
plugs. The occurrence of the spark at the plug is practically simul¬ 
taneous with the opening of the interrupter contacts. 

Delco System. A magneto-type interrupter, substantially sim¬ 
ilar to that of the Connecticut system except that it is provided 
with an automatic-spark advance, is used, as shown in Fig. 126. 
The arm B carries the movable contact D and a flber-striking 
lug which bears against the four-part cam and is lifted by its revo- 

















182 


ELECTRICAL EQUIPMENT 



Fig. 127. 


Diagram of Earlier Model of Delco 
Interrupter 


lution against the tension of the leaf spring held against the inner 
wall of the housing. The stationary contact is at C and is adjusted 

by means of the screw and 
locked in place by the nut 
N. These contacts should 
be so adjusted that when 
the fiber block on B is on 
top of one of the lobes 
of the cam, the contacts 
should open sufficiently to 
allow the gage on the dis¬ 
tributor wrench, provided 
with the system, to’ close 
the gap. As in the Con¬ 
necticut interrupter, the 
contacts normally remain 
closed, being opened mo¬ 
mentarily by the cam, which has as many projections as there are cyl¬ 
inders to be fired. This is the later model of Delco interrupter (1916). 

Earlier Model Inter¬ 
rupter. In an earlier model 
which will be found on a 
great many cars, the con¬ 
tacts are normally held 
open, Fig. 127. The mov¬ 
able contact is carried on 
a straight spring blade to 
which is attached a bent 
spring blade B held against 
the cam by the spring E. 
The latter also places the 
spring C under slight ten¬ 
sion and holds the mov¬ 
able contact away from 
the stationary contact D. 
When the projection of the 
cam strikes the raised portion of B, it deflects the latter and allows 
the contact points to come together. As it passes the bump on B, E 


^eiiifance Unrf 


//OTE' W/ien confacf ar'jrr rj ort fop 
of a /o6e of ffie cam fftfs cfisfa/rce 
■aAou/ci 6e ftffeert ffiousa7Tcff/ts of an 
tncft. / 

V 



Contacts 
should open 
ten thousanMi 
of an fncfi. 


Fig. 128. Delco Timer with Resistance Unit 










































ELECTRICAL EQUIPMENT 


183 


draws B back sharply, its end strikes C, and the contacts are suddenly 
opened, the duration of the contact varying with the speed of the 
engine. 

Thner with Resistance Unit. Mention has been made of the fact 
that the contacts of the interrupter in the battery system of ignition 
are normally closed, just as they are in the magneto interrupter, 
only the circuit being opened at this point at the time of ignition. 
Owing to the rapidity of their action and the extremely short interval 



Fig. 129. Four-Cylinder Battery Ignition Unit on Dodge Car (1917)—Coil at Left 
Courtesy of Dayton Engineering Laboratories Company, Dayton, Ohio 

between contacts in the interrupter of a high-speed engine, this calls 
for a very small current consumption. Should the ignition switch 
be left closed when leaving the car, however, the timer cam is just 
as likely to stop in the closed position as in the open, and this small 
steady discharge will result in exhausting the storage battery. To 
prevent this waste of current and possible damage to the contacts 
and coil, a later type of timer has been provided with a resistance 
unit. This is shown on the left-hand terminal of the timer. Fig. 128, 
which illustrates the type used on the Cole, among others. The unit 










184 


ELECTRICAL EQUIPMENT 


consists of a small open coil of high-resistance wire wound upon a 


porcelain spool mounted on the head of the terminal. 



All the current passing through the timer must first pass 
through this resistance winding, but, owing to the extremely short 
period it continues between interruptions due to the opening of the 
contact points, the resistance wire remains cool. When the switch 
has been left on with the engine idle, however, the current is then 

continuous and of greater 
~ ' value, and it brings the 

resistance wire to a red 
heat in a comparatively 
short time. At this 
temperature, its resist¬ 
ance increases so greatly 
that it permits very lit¬ 
tle current to pass. It 
will also be noted that 
the condenser is mounted 
on the timer in this case. 

As the spark occurs 
at the instant the timer 
contacts are opened, the 
ignition timing may be 
altered by moving cam A 
with relation to its shaft, 
which is done by loosen¬ 
ing screw B. Turning 
the cam in a clockwise 
direction, or to the right, 
advances the time of igni¬ 
tion, and to the left, or 
counter-clockwise, retards it. The distributor used in connection 
with this timer is provided with automatic spark advance, as well 
as with the usual manual control on the steering wheel. Typical 
distributors for five-, eight-, and twelve-cylinder installations are 
shown in Figs. 129, 130, and 131, respectively, the first being found 
in the 1917 Dodge, the second in the 1917 Cadillac, and the third in 
the 1917 Haynes. In Fig. 132 is illustrated a dual-type timer 


Fig. 130. Eight-Cylind«r Distributor and Drive (Delco) 
as Used on 1917 Cadillac 

Courtesy of Dayton Engineering Laboratories Company, 
Dayton, Ohio 





ELECTRICAL EQUIPMENT 


185 


having independent interrupter contacts for both the battery and 
the magneto. Apart from this feature, its construction is the same. 
This type is employed on the Oakland. 

Delco Ignition Relay. As originally designed, the Delco igni¬ 
tion system was provided with a relay to produce a series of sparks 
for starting and a single spark when running. While this is no 
longer a part of the system, it is in use on thousands of cars now in 



Fig. 131. Twelve-Cylinder Delco Distributor on Haynes (1917) 
Courtesy of Dayton Engineering Laboratories Company, Dayton, Ohio 


service. ^ The relay itself is shown in Fig. 133, together with a 
diagram of its connections. It consists of an electromagnet with 
two windings, one of coarse wire and one of fine wire, similar to a 
battery cut-out. The coarse winding produces a greater magnetic 
effect than the fine winding and exerts sufficient pull on the movable 
armature when at rest to draw it toward the end of the magnet core. 
It is so connected that the current ceases to flow through it when 






186 


ELECTRICAL EQUIPMENT 


the contacts C are open. The fine winding is connected to the 
contacts so that it holds the armature of the relay open after the 
circuit of the coarse winding is broken at the contacts C, and is 
known as the ‘‘holding coil”. Its magnetic pull is not sufficient to 
draw the armature down from its position of rest, but strong enough 
to hold it there after it has been pulled down by the other winding. 
A condenser is connected around the contacts C to suppress the arc 
and increase the speed of working. A three-way switch is provided, 



Fig. 132. Delco Dual Type Timer with Two Sets of Contacts 


having a point for “starting”, one for “running”, and a neutral 
point. When on the starting point, the relay operates continuously, 
the same as a vibrator, and produces a series of sparks; on the 
running point, the fine winding of the coil is energized and the con¬ 
tacts held together, thus producing a single spark. 

Interrupter for Higher-Speed Engines. For the extremely high¬ 
speed engines now coming into general use, a special interrupter 
having two sets of contact points and a three-part cam is employed 
(for six-cylinder motors). Each set of contacts is connected to a 
relay so that the circuit is closed through the two relays alternately, 



























































ELECTRICAL EQUIPMENT 


187 


thus giving each magnetic interrupter more time in which to open 
and close the circuit. Fig. 134 illustrates the connections of a 
system of this type, the interrupter being shown just above the 
coil, while Fig. 135 shows the complete wiring diagram. 

Adjusting Delco Ignition Relay. The ignition relay is con¬ 
nected in the dry-battery circuit and serves to interrupt the primary- 




Fig. 133. Diagram of Delco Ignition Relay and Its Internal Connections 
Courtesy of Dayton Engineering Laboratories Company, Dayton, Ohio 

ignition circuit, inducing a high-tension current in the secondary so 
that a spark will occur at the plugs. 

Methods of Connecting Relay. The relay is connected to the 
ignition coil and the distributor in two ways, as shown in Figs. 135 
and 136. The operation of the relay, which varies slightly with 
its connection to the external circuit, is discussed as follows: 






































































188 


ELECTRICAL EQUIPMENT 


(a) (See Figs. 133 and 135 interchangeably.) The contacts C 
of the relay and the coil A are in series, with a special set of timer 
contacts on the dual distributor. When these contacts are closed 
(by the revolution of the fiber-timing cam), current passes through 
the ignition coil and timer contacts and contacts C of the relay and 
through the coil A, energizing the latter. This immediately causes 
the armature to open, thus interrupting the primary circuit and caus¬ 
ing a spark at the plug. As soon as the circuit is interrupted, coil A 
is no longer energized and contacts C open again, this being repeated 
indefinitely as long as the timer contacts are together. This occurs 



Fig. 134. Diagram of Delco Special Interruper for High-Speed Engines 
Courtesy of “The Horseless Age” 


only when the circuit between the terminals No. 6 and No. 7 on the 
combination ignition and lighting switch. Fig. 135, is open, which is 
accomplished by pushing the starting button. If it is desired to 
obtain but a single spark, as for running (the vibrating contact 
giving the repeated spark being simply for starting), the holding coil. 
Fig. 133, is energized so that when the armature touches the core, it 
is held there and a single spark, similar to that produced by generator 
or storage battery ignition, is obtained. This coil is energized when 
the terminals No. 6 and No. 7 on the combination switch. Fig. 135, 
are closed, which is accomplished by releasing the starting button. 

(b) (See Fig. 136.) This is the method used in connecting the 
ignition relay on the Delco Junior system for 1914. The ignition 






























































ELECTRICAL EQUIPMENT 


189 


switch completes the primary circuit, and, in this manner of using 
the relay, the holding-coil circuit is completed through the timer 





f-rome of car Hnoujn as Ground' 

Fig. 135. Wiring Diagram of Delco Ignition System Using Relay 


contacts. Therefore, a vibrating spark is obtained as long as the 
timer contacts are open, and the timing of this vibrating spark is 
obtained by the action of the contacts upon the holding coil itself, 




















































190 


ELECTRICAL EQUIPMENT 


For this reason, this method of using the relay causes much later 
ignition than is obtained with the method described in the previous 
paragraphs. 

Adjustments. The following points should be borne in mind 
when adjusting the relay: When the armature B, Fig. 133, is pressed 



down with the finger, thus opening contact C, there should be abso¬ 
lutely no motion of the blade G, Fig. 137, carrying the lower contact. 
The gap at C should be approximately .005 inch (thickness of a 
piece of paper similar to, or slightly heavier than, that on which this 
book is printed). When blade A is lifted gently by hand, the con-- 






















































ELECTRICAL EQUIPMENT 


191 


tacts at C should open to the same gap as before, viz, .005. The 
points at C must make perfect contact. 

There are two adjustments to the relay: the air gap at I, Fig. 
133, which increases the distance at C also; and the tension exerted 
by the spring A, Fig. 137, on the contacts C. Slight adjustment of 
the air gap I may be made, but in no event should the distance 
between the contacts C be increased very much over the value men- 



Fig. 137. Method of “Crowning” the Spring, Delco Ignition Relay 


tioned above. If it is impossible to obtain a sufficiently powerful 
spark by adjusting the air gap slightly, it will be necessary to 
increase the tension of the spring A. This can be done hy crowning 
the spring with a pair of duck-bill pliers. The spring is loosely held 
between the jaws of the pliers near the end at which it is screwed 
down to the relay frame, and the pliers are then moved along the spring 
with a downward pressure and a twist to the right, as indicated in 
Fig. 137. When properly carried out, this operation will cause the 
spring to assume a curve similar to that shown in the illustration. 
Fig. 138, and a very noticeable increase in the tension of the contacts 



Fig. 138. How Springs Should Look when Properly “Crowned” 


will have been effected. Care must also be taken to see that the 
armature makes a right angle (90°) and that it is free on its pin. 

When properly adjusted, the ignition relay should take .6 ampere 
when furnishing a vibrating spark with the engine at rest, and 
the reading of a dead beat type of ammeter, similar to the Weston 
miniature-precision instruments, should be approximately .15 ampere 
when the ignition switch is thrown on. 































192 ELECTRICAL EQUIPMENT 

TESTING, ADJUSTMENT, AND MAINTENANCE 

Trouble Nearly Eliminated by Efficient Devices. With modern 
equipment, trouble from electrical sources has been decreased to an 
almost irreducible minimum and with a knowledge of the rudiments 
plus consistent observance of a few simple rules, these troubles can 
usually be remedied without calling in outside assistance. Causes 
of failure are the most important thing to remember as, with these 
in mind, it is far easier to trace the trouble logically than where the 
usual aimless hunt is undertaken on the chance of striking the cause. 
It must also be borne in mind that all causes of motor stoppage are 
not electrical. A dry gasoline tank, a plugged-up gasoline feed line 
or a choked carbureter, failure of a gasoline pressure-feed system, or 
a stopped-up air vent in a gravity-feed gasoline tank will have the 
same effect, though one or all of them have not infrequently been 
attributed to the ignition system. 

Causes of Failure. Failures may be generally classed under 
three heads: short circuits or grounds; failure of current supply; and 
failure of ignition devices, such as contact breakers, distributors, 
vibrators, coils, spark plugs, wiring, connections, condensers, etc. 

Short'Circuits. Mdien a motor that has previously been running 
normally suddenly stops dead, the indication is almost invariably 
that of a short-circuit or ground. The difference between the two 
is that a short circuit takes place between two wires or other parts 
of the system, while a ground is the contact of a chafed wire or other 
exposed part with some portion of the metal foundation of the car, 
such as the frame or motor. The effect is the same in either case 
in that the current takes a shorter path and does not reach the 
spark plugs. Either may occur in the low- or high-tension wiring, 
i.e., between the contact breaker and the coil or the battery and the 
coil; or between the secondary side of the coil and distributor. 
Owing to the high voltage of the latter, grounding is more apt to 
result there either from a chafed wire or from a frayed end coming 
in contact with the motor or other metal. Failure from this cause 
can frequently be detected by sparking at the point of breakdown. 
An “open circuit” in one of the main feed cables, such as that con¬ 
necting the magneto to the primary of the coil in a dual system, 
or the secondary of the coil to the distributor, or the battery cable 
in a battery system will naturally have the same effect. The cause 


ELECTRICAL EQUIPMENT 


193 


is usually a loose connection; sometimes, though rarely, a broken 
wire. If the connection has not parted entirely, irregular firing 
will result. 

Failure of Current Supply. Failure of current supply will usually 
result in erratic running as the current weakens until it reaches a 
point where it is no longer adequate and the motor stops. But the 
symptoms in this case are the same as in gradual failure of the fuel 
supply, either through a choked carbureter nozzle, partially 
obstructed feed line, stopped air vent, lack of pressure, or the empty¬ 
ing of the tank. The motor will run by fits and starts with irregular 
missing at different cylinders. Defection of the contact breaker or 
distributor may also manifest itself either by similar erratic opera¬ 
tion or by sudden stopping. 

Weak Magnets. When the engine fires regularly on the battery 
but will not do so on the magneto except above a certain speed, it 
indicates that the magnets are weak and need remagnetizing. Heat 
and vibration weaken the magnets, so that on some cars it is neces¬ 
sary to overhaul the magneto every five or six thousand miles, 
whereas, on others, the magnetism shows no appreciable falling off 
after two or three seasons’ use. With a new or recently overhauled 
magneto it should be easy to start on the magneto by spinning (by 
hand), but this is not conclusive as some engines will never start 
on the magneto. 

Testing. Inspection of Wiring. Examination of the wiring and 
other parts of the system will usually suffice to reveal short circuits 
or grounds, or by making emergency connection with extra wire, 
proper operation through the latter indicating a failure of the parts 
of the wiring system thus replaced. Extra wire should always be 
carried on the car for this purpose. With the dual type of ignition 
system so generally employed, see that the zinc-containing case or 
the protruding terminals of dry cells are not allowed to come into 
contact with the metal battery box as this will cause a ground that 
is difficult to locate. The best preventive is a small wood container 
to insulate these cells from contact with any metal. Water falling 
on the high-tension cables will cause serious leaks that will not show 
in the form of sparks. Above all, every part of the system must be 
kept dry; sufficient precautions are frequently omitted when washing 
the car. 


194 


ELECTRICAL EQUIPMENT 


Inspection of Current Supply. To make certain that erratic 
operation is not due to failing current supply, a small testing instru¬ 
ment, such as that shown in Fig. 139, should be carried on the car. 
This is the Hoyt multimeter, which gives an independent ampere and 
voltage reading by dials on both sides of the instrument. Either may 
be used separately or both simultaneously. For dry battery testing 
an instrument with a high reading ampere scale is necessary, that 
shown being for the current consumption of a battery-operated 
vibrator coil where economy is essential. Dry cells should test at 
least 10 to 12 amperes to give an efficient spark, though they will 
frequently operate on less. An ammeter should never be employed 
on a storage battery. For [this 
the voltmeter affords the best 
test. Full instructions for the • 
care of storage batteries are 
given in the article on “Electric 
Vehicles”. 

Solving Troubles. Inspection 
of Contact Breaker. Derange¬ 
ment of the contact breaker is 
almost invariably due to wear. 

In time the contact points will 
burn away unevenly, this being 
more rapid in older types not 
provided with a condenser. If 
not too far gone, straightening 
with a very fine file and adjust¬ 
ment will remedy this. Or they may wear down so far that the cam no 
longer separates them, thus preventing the secondary coil from coming 
into operation, as the circuit is not opened in the primary and no spark 
takes place at the plugs. Ample adjustment is provided to take 
care of this and with a little truing up of the points the trouble will 
be cured. These contacts will sometimes wear to a point at which 
the cam will still continue to open them when running at high speed, 
but fails to do so when the motor is cranked for starting (dual sys¬ 
tem). This provides the anomalous case of a motor running per¬ 
fectly the day before and absolutely refusing to start when next 
cranked. It represents one of the obscure ailments mentioned. 



Fig. 139. Hoyt Testing Volt •Ammeter 
for Automobile Use 





ELECTRICAL EQUIPMENT 195 

as every other part of the system will respond to the usual 
tests. 

Remember Effect of Compression on Spark. The effect of com¬ 
pression on the spark must also be borne in mind, as an apparently 
efficient spark with the plug out of the cylinder is not equally effec¬ 
tive when subjected to the compression. Partial failure of the cur¬ 
rent supply is the cause in this case, due to weak dry cells or an 
almost wholly discharged storage battery causing a drop in the 
voltage. Or it may result from spark plug points that have been 
burned away until the gap is too great, ^ inch being the maximum 
distance recommended. 

Leakage at Distributor. Leakage may occasionally occur at the 
distributor due to the use of an excessive amount of lubricating oil 
which picks up carbon dust, the latter being carried around 
by the revolving arm until it forms a path for the high-tension 
current. 

Spark Plugs. A broken spark plug porcelain or an internal 
short circuit of the plug, neither of which may be evidenced exter¬ 
nally, will cause missing at that cylinder. 

Erratic firing and a very perceptible loss of power will result 
from the gaps of the spark plugs being too large. With the powerful 
current supplied by a storage battery or by the modern magneto this 
takes place by the burning away of the points of the electrodes in a 
comparatively short time, it being nothing unusual for the ^-inch 
gap to increase to almost J inch in a few weeks’ running. This is 
particularly the case with the cheaper plugs which have iron-wire 
electrodes; they may be adjusted with the pliers, however, until 
there is no longer sufficient electrode left to adjust. 

Loss of power will also be occasioned by a plug that is not tight 
in the cylinder or where the plug itself is not tight internally. Scpiirt 
a few drops of oil around the base of the plug on the cylinder and 
also on the porcelain of the plug. When the engine is running 
bubbles will form at these points: if the plug itself is at fault, a quar¬ 
ter-turn of the nut holding the porcelain in place will usually seat it 
on the gasket and overcome any leakage at that point; in case of 
leakage around the thread of the plug, a new asbestos gasket under 
it or a slight tightening of the plug itself where of the iron-pipe 
thread class will remedy the trouble. Cleaning at intervals with a 


1% 


ELECTRICAL EQUIPMENT 


stiff brush and gasoline will prevent short-circuiting through an 
accumulation of carbon on the porcelain and walls of the shell. 

Sharking at Safety Gap. In all magnetos of the true high- 
tension type, the safety gap is incorporated in the magneto itself: 
in dual-ignition systems it is in the coil, as the latter must be pro¬ 
tected from the battery current as well as from that of the mag¬ 
neto. Sparking at the safety gap is an indication that there is an 
opening in the circuit greater than the resistance of the secondary 
winding of the coil, and unless the spark bridged the safety gap, the 
insulation of the high-tension winding would be punctured. This 
opening may be a spark plug whose points are too far apart or a 
connection that has dropped off either at the plug or at the coil. 
Owing to its high voltage the current will jump- any gap smaller 
than that of the safety gap with no perceptible difference in the 
firing, so that loose connections on the high-tension side seldom 
cause trouble until they actually separate. A piece of metal acci¬ 
dentally falling on it or an accumulation of any conducting material 
such as dirt or moisture will short-circuit the secondary of the coil 
through the safety gap and no current will reach the plugs. Frayed 
terminals in which one or more of the strands of the flexible wire 
j)rotrude and touch adjacent objects are sometimes responsible for 
a similar result; the remedy is to wind with friction tape. 

Breakdown of Magneto. On cars employing a true high-tension 
type of magneto, the battery system is entirely independent, as a 
rule, so that a fault in one never involves the other. Where failure 
of the magneto is not due to faulty operation of the interrupter, it 
may be inspected with the aid of the test lamp described in connec¬ 
tion with starting and lighting systems. Trace the various circuits 
of the magneto in question; apply the points to the opposite sides 
of the condenser. The lamp should not light; if it does, the con¬ 
denser has broken down and must be replaced. Test the primary 
and secondary windings of the magneto in the same way; the lamp 
should light in each case; if it does not, there is a break in that par¬ 
ticular winding and a new armature will be required. In the case 
of the dual-type magneto there is only one winding on the arma¬ 
ture, and many of the older makes (1910 or earlier) have no conden¬ 
ser. Many of these older magnetos in the cheaper grades are fitted 
with plain bearings and the wear of the latter may allow the arma- 


ELECTRICAL EQUIPMENT 


107 


ture to bind against the pole pieces, or lack of oil may cause the 
shaft to bind in its bearinga 

When a magneto is taken apart for any reason it must always be 
assembled with the magnets in the same relative position as formerly, 
otherwise their polarity will be reversed and the magneto will be 
inoperative. The magnets must never be left off the machine, even 
temporarily, without placing a bar of iron or steel across their poles 
to serve as an armature or “keeper”; unless this is done, they will 
lose their magnetism rapidly. Remagnetizing the magnets of a 
machine that has become weakened through long use is a simple 


Fig. 140. Design for Magnet Recharger 
Courtesy of “The Horseless Age” 



process and small electromagnets for this purpose are now to be 
had for garage use. They will operate, of course, only on direct 
current. 

Remagnetizing. As misfiring at low speeds may be due to 
causes other than weak magnets on the magneto, the strength of 
the latter should be tested before deciding that it is necessary to 
remagnetize them. With the engine running, unclip one of the spark 
plug leads and hold it close to the terminal. If the magneto is 
developing a powerful current, it will jump a gap of | inch or more; 
should it not produce a spark at least \ inch long it needs remagnet¬ 
izing. In recharging the magnets their original polarity must be 
preserved, as otherwise it will be necessary to shift their locations 


























































































198 


ELECTRICAL EQUIPMENT 


in reassembling them. Accordingly, it is important that unlike 
poles of the permanent magnets and of the electromagnet be brought 
together; i.e., the north pole of the permanent magnet to the south 
pole of the recharging magnet and vice versa. To insure this, the 
current should be turned into the recharging magnet and the other 
magnet held freely a short distance from its poles. As unlike poles 
attract and like poles repel, the magnet will find its own proper 
position, if allowed to do so. If forcibly held against the poles of 
the recharging magnet regardless of polarity, the strength of the 
electromagnet is so much greater than that of the weakened per¬ 
manent magnets that it will reverse their polarity. 



Fig. 141. Diagram of Connections of Magnet Recharger 
Courtesy of “The Horseless Age” 


In recharging, set the magnet on top of the charger after its 
polarity has been determined and rock the magnet back and forth 
on its pole edges a number of times; then lay it on its side with its 
poles away from you and, extending just beyond the far edges of 
the recharging magnet poles, apply a keeper to the magnet poles, 
switch off the current and withdraw the magnet sideways from the 
recharger. The keeper should remain in place until the magnets are 
reassembled on the magneto. 

Magnet Recharger. Electromagnets designed for this purpose 
and built specially for garage use are now on the market, or one 
may be made with little trouble. The following design. Fig. 140, 





































ELECTRICAL EQUIPMENT 


199 


is from The Horseless Age. The cores of the magnet are made of 
soft bar steel 1 inch in diameter and 3 inches long. They are secured 
to a base measuring hj by IJ by f inches and are provided with pole 
pieces measuring If by If by f inches. All contacting surfaces 
should be absolutely flat and square so that there will be good 
metallic contact over the entire surfaces. Before the wire is wound 
on them, the magnets must be insulated. A spool may be formed 
by placing a fiber ring at each end of the magnet cores, and a better 
job may be made by turning down a l|-inch bar, leaving a thin 
collar of the original diameter at one end. This will support the 
fiber ring at that end while the other rests against the pole piece. 
The core between the fiber rings is then insulated by wrapping with 
several layers of muslin which is given a coat of shellac in alcohol 
and allowed to dry. 

The winding to be applied depends on the voltage to be used. 
For a 6-volt battery, wind on three layers of No. 12 double cotton- 
covered magnet wire; for a 110-volt circuit, eight layers of No. 22 
double cotton-covered magnet wire. The ends or leads of the wire 
are then taped and the outer layers of the coils shellaced to make 
the exposed cotton insulation more enduring. Connect the coils 
together so that if the current flows through one right-handed, it 
flows through the other left-handed, when looked at from above. 
Fig. 141» Mount the completed magnet on a wooden base large 
enough to carry a single-pole switch and a binding post. The 

• 

battery or lighting mains are connected to the binding post and the 
free terminal of the switch; the other terminal of the switch being 
connected to one end of the magnet coil and the other terminal of 
the latter to the binding post. Where designed for 110-volt current, 
it will be preferable to use a double-pole switch mounted on a porce¬ 
lain base with two screw-plug fuses; 10-ampere fuse plugs being 
screwed into the sockets. The free ends of the coil are then con¬ 
nected directly to the terminals of the switch at the plugs and the 
source of current is connected to the other end of the switch. The 
windings specified will heat up quickly, when connected to current 
sources of the voltages given, so that the switch should never be left 
closed more than a few minutes at a time. 

Where direct-current mains are accessible, the magnets may be 
recharged without dismounting them from the magneto. Being 


200 


ELECTRICAL EQUIPMENT 


flexible and well insulated, lamp cord may be used and must be 
wound directly on the magnets. The bared ends of the cord should 
be twisted together so that the two wires form a single conductor. 
Wrap on about fifty turns and connect this winding to the main 
switch through a 10-ampere fuse. Particular care must be exercised 
to make the connections so that the magnets will not have their 
polarity reversed. A current of high value will flow through the 
winding during the brief time that it will take to blow the fuse. 
While this method obviates the necessity of taking the magneto 
apart, the latter involves so little labor that the use of the magnet 
recharger usually will be found preferable, particularly where there 
is any doubt as to the polarity. 

Care of Ford Magneto. Dirt will sometimes accumulate under 
the collector brush or on the collector ring and reduce the current 

output. As a guide to the operation of the 
Ford magneto, the Hoyt magnetometer. 
Fig. 142, has been devised. The calibration 
of this is purely arbitrary, the letters repre¬ 
senting Poor, Medium, Good, and Excellent. 
Probably end play in the bearings is the 
most frequent cause of poor operation of 
the Ford magneto. This is due to wear of 
the main crankshaft bearings which permits 
Fig. i42.^^Hoyt^Ma^gnetometer magnets to rotate at a greater distance 

from the coils than originally intended. 
Taking up this play or replacing the bearings is naturally the remedy. 
Small particles of metal may sometimes lodge beneath the ribbon 
terminals of the coils, or the latter may become so thoroughly 
impregnated with metallic dust as to ground them, making them 
inoperative. Cleaning and renewal of the oil in the magneto housing 
will remedy this. To test the coils, four or six dry cells connected 
in series should be used. Attach one terminal of the battery to the 
collector brush or insulated plug at the top of the magneto and the 
other terminal to the connection where the last coil is grounded to 
the supporting plate. Then with a piece of soft iron touch the iron 
core of each coil to see it if is strongly magnetized. It should take 
some effort to pull the iron away. A coil that does not respond 
properly is probably grounded. Weak magnets are occasionally 






ELECTRICAL EQUIPMENT 


201 


found to be the trouble, but this is comparatively rare, as well-made 
permanent magnets are usually good for years of service. When 
they are found, the best remedy is to replace the entire set, particu¬ 
larly as the cost is low. 

SUMMARY OF IGNITION INSTRUCTIONS 

Q. How many different systems of ignition are in use on the 
automobile today? 

A. Generally speaking, only one, known as the high-tension 
system. The low-tension system used in earlier days has been obso¬ 
lete for a number of years. The single classification, however, may 
be subdivided into several others which are known by their dis¬ 
tinguishing features, the first being determined by the source of cur¬ 
rent supply, as magneto- and battery-ignition systems. These two 
classes may be divided further according to the type of magneto 
employed, such as the duplex, the dual, and the double-spark types. 
All battery systems are fundamentally the same, only differing in 
the type of circuit breaker and distributor employed, the mounting 
of the latter, i.e., whether direct driven from the engine or combined 
with the lighting generator, and in the type of controlling switches 
and auxiliary devices. 

DIFFERENT SYSTEMS 

Q. Why is the system generally used termed “high=tension” 
system? 

A. Because the current must be passed through a step-up 
transformer or coil to impress, upon it a sufficiently high voltage to 
cause it to jump the air gap in the spark plug. 

Low=Tension System 

« 

Q. Is the old low=tension make=and=break system entirely 
obsolete? 

A. Since about 1909, it has not been used on the automobile 
but is still generally employed on small two-cycle marine engines 
and on stationary engines. 

Q. Why is it not suitable for automobile engines? 

A. It will not work satisfactorily at high speeds since its time 
factor is limited by mechanical reasons, i.e., the inertia of the mov¬ 
able electrodes of the low-tension spark plugs, whereas, in the high- 


202 


ELECTRICAL EQUIPMENT 


tension system, only electrical lag has to be compensated for. It 
requires a skilled mechanic to time the spark plugs properly and they 
will not stay in adjustment for very long. 

Q. What is the chief attention it needs as employed on marine 
and stationary engines today? 

A. Keeping the electrodes clean; the current burns a film of 
oxide on the contacts and this insulates them to an extent where 
the low-voltage current will not pass. The timing of the plugs also 
needs regular attention as the hammering action of their operation 
tends to throw them out of adjustment. Considerable current is 
required for the efficient operation of the low-tension plugs, so that 
where used with batteries as on the motor boat, the cells frequently 
become exhausted in a comparatively short time. 

Q. How can the low=tension plugs be adjusted to give them 
the proper timing? 

A. Turn the engine over slowly by hand and watch the action 
of the plug. Its contacts should come together when the piston is 
three-fourths of the way up on the compression stroke; they should 
snap apart to cause the spark, the advance lever being in the 
retarded position, when the piston is at upper dead center. Provision 
is usually made for increasing or decreasing the length of the rod 
that operates the plug. If the spark is occurring too late, causing 
a falling off in the power, shorten the rod sufficiently by the adjust¬ 
ment to give the timing suggested above and lock tightly; if too 
early, lengthen it just enough to overcome any hammering that 
this would cause. 

Q. Why should the plug close the circuit so long before the 
piston reaches upper center? 

A. To give the coil sufficient time to “build up”, i.e., for its 
core to become “saturated”, or thoroughly magnetized, as the 
efficiency of The spark produced'depends upon this. 

Q. How does the coil of a low=tension system act? 

A. It is a single winding of coarse wire on a very heavy core of 
fine iron wires, i.e., a coil having a high self-inductance. When the 
circuit has been closed a sufficient length of time to permit this core 
to become saturated and is then suddenly broken, the current util¬ 
ized to magnetize the core is redelivered to the coil and causes an 
arc at the plug as its contacts separate. The current producing this 


ELECTRICAL EQUIPMENT 


203 


arc is of much greater volume and at considerably higher voltage 
than could he obtained l)y making and breaking the battery.circuit 
without a coil in it. 

Q. Does the coil ever need attention? 

A. Only to see that its connections are clean and tight and 
that it is kept dry; owing to the solidity of its construction, failure of 
the coil itself is almost unknown. Test by holding one terminal of 
a three-cell or four-cell dry battery on one binding post and wiping 
the other with the wire from the other side of the battery circuit; a 
bright flash should result. If it does not, see if the wire has broken 
near one of the binding posts as this may result from vibration. 

Q. Is this the only low=tension system used? 

A. No. Several makes of magnetic plugs have been used in 
connection with low-tension systems. Each plug is a solenoid the 
plunger of which makes and breaks the contact electrically. No 
mechanism is necessary to operate the plug but a timer must be used 
in the circuit to close the latter slightly in advance of the time for 
the spark to occur. This timer is the same as that used in the 
primary circuit of high-tension systems employing vibrator coils, as 
on the Ford. 

Q. What difficulty is usually encountered with magnetic plugs? 

A. They seldom withstand the heat of the engine for any great 
length of time, so that the insulation fails. Apart from this the 
troubles encountered are the same as with any other system using 
movable contacts, i.e., dirt on the contact points, failure to make 
contact, broken connections, weak battery, etc. 

High=Tension System 

Q. Of what does a high=tension system consist? 

A. The essential parts of a high-tension ignition system are: 
(1) a source of current, such as a dry battery, the storage battery of 
the lighting and starting system, the direct-current generator of the 
latter, or a magneto; (2) a- step-up transformer or induction coil, 
the primary winding of which is in circuit with the source of current 
supply; (3) a contact breaker or interrupter to open this circuit 
periodically, i.e., once every other revolution for each cylinder of a 
four-cycle engine; (4) a distributor in circuit with the secondary 
winding of the coil and provided with as many contacts as there are 


204 


ELECTRICAL EQUIPMENT 


cylinders; (5) a spark plug for each cylinder; (6) primary and sec¬ 
ondary cables for the respective connections, and a controlling 
switch to open and close the supply circuit or to change from one 
supply circuit to another, where both a battery and a magneto are 
employed. 

Q. How do these essentials vary in different systems? 

A. Where a battery is depended upon for the current supply, 
the interrupter and the distributor are usually combined in an 
independent device which is driven from the camshaft of the engine. 

In the case of a magneto, both the interrupter and the dis¬ 
tributor are integral with it. This does not apply to the Ford 
magneto which has a separate low-tension timer and uses no dis¬ 
tributor, as there is a vibrating coil for each cylinder. 

In what are commonly known as modern battery systems, the 
timer and distributer may be either mounted separately, as first 
mentioned, or combined with the lighting generator. 

CURRENT SUPPLY AND APPLICATION 

Magnetos 

Q. How many types of magnetos are there in general use? 

A. Two general classes, the low-tension and the high-tension, 
and various special types, such as the dual, the double-spark, the 
duplex, and the inductor magnetos. 

Q. What is the difference between low=tension and the high= 
tension magnetos? 

A. The low-tension magneto has only a single winding on its 
armature the current being generated at low voltage and trans¬ 
formed by passing through an independent coil, whereas the high- 
tension magneto generates the current in one winding and steps it 
up through another, both on the same armature. 

Q. What is a dual magneto and why is it so called? 

A. It is a low-tension type, the interrupter and distributor of 
which are also employed in connection with a battery for starting. 
It is so called because these essentials are common to both the 
magneto and the battery sides of the system. 

Q. What is a double=spark magneto? 

A. One provided with two distributors designed to produce 
two sparks simultaneously at two different plugs in the same cylinder. 


ELECTRICAL EQUIPMENT 


205 


Q. What is a duplex magneto? 

A. One designed to permit of passing the battery current 
through the armature of the magneto to facilitate starting, the 
magneto and battery both acting together to produce the spark at 
low speeds. To accomplish this a commutator is mounted on the 
armature shaft and the battery connected to it, the magneto being 
of the high-tension type. This commutator causes the battery 
current to alternate in direction with that produced by the magneto 
so that it is said to be “in phase” with the latter. 

Q. What is an inductor magneto and how does it differ? 

A. An inductor is employed instead of an armature, the 
windings being stationary. The inductor is simply a revolving 
piece of metal which alternately opens and closes the magnetic 
circuit. In the K-W inductor magneto this winding is of copper 
ribbon and is placed between the poles of the inductor; in the Dixie 
magneto it is a conventional induction coil placed in the hollow of 
the magnets above the inductor. 

Q. Why can a magneto not be run in either direction equally 
well? 

A. Owing to the contour of the cam which serves to open the 
contacts of the interrupter. This must be designed to operate the 
magneto either as a “right-hand” or a “left-hand” machine. 

Q. How is a magneto timed? 

A. Disconnect its drive from the engine. Turn engine over 
by hand until the piston of cylinder No. 1 is exactly at the upper 
dead center on the firing stroke. Turn the armature shaft of the 
magneto to a point where the contacts of the interrupter are just 
beginning to open; the brush of the distributor which is then making 
contact with the distributor segment should be connected to the 
spark plug of cylinder No. 1. The next brush should be connected 
to cylinder No. 2 or No. 3, according to whether the firing order is 
1_ 2- 4- 3 or 1- 3- 4- 2. The armature of the magneto should be 
coupled to its driving shaft in the position as determined for the 
first cylinder. 

Q. If after timing a magneto in this manner, it is found that 
the spark=timing lever does not give sufficient advance or retard, 
what should be done? 

A. Remove the cover from the distributor housing of the 


200 


ELECTRICAL EQUIPMENT 


magneto, the piston of cylinder No. 1 being at upper dead center of 
firing stroke and the interrupter contacts just about to open as 
directed for timing. Note the relative position of the segment and 
the distributor brush which should be making contact with it. If 
the segment has already passed the brush, the spark-timing lever 
being at the maximum advance position, remove the distributor 
gear from its shaft and from engagement with the pinion on the 
armature shaft. Move it back one tooth (against the direction of 
its rotation which is the opposite of that of the armature pinion) 
and remesh with pinion. If this does not bring it into contact with 
the brush, move back another tooth. Should the distributor seg¬ 
ment not have reached the brush when in the position as given 
above, move the distributor gear forward, or in the direction of its 
rotation, one or two teeth, and remesh. 

Q. How can the various types of magnetos be identified, as 
installed on car? 

A. The two types in most general use may be distinguished at 
once by their external connections. The so-called dual type can be 
identified by its separate coil, or transformer, mounted on the face, 
or the front, of the dash, under the hood, and the connecting cables 
from the magneto to this coil. One of these connections is for the 
primary of the coil, and the other is for the secondary; the other 
ends of both coils are joined together and copnected to a common 
ground wire, so that the coil has only three connections. The true 
high-tension type can at once be recognized by the fact that its 
only external wires are those connecting the distributor plate of the 
magneto directly with the spark plugs. 

Q. Of these various types, which are most commonly used? 

A. The dual type will be found on most low-priced cars 
(except the Ford), and the’straight high-tension type on higher priced 
cars not using battery ignition. 

Q. In searching for faults, is it easier to locate trouble in one 
type than in the other,' and is the procedure different in each case? 

A. Owing to its having but a single winding on its armature, 
and to the fact that all of its connections are external, the dual low- 
tension magneto is the simpler of the two; but the exposed location 
of its connections makes them more subject to default than those 
of the high-tension magneto. The procedure differs in that failure 


ELECTRICAL EQUIPMENT 


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to operate, in the case of a dual magneto, may be caused by injury 
to, or the breaking of, some of these external connections; whereas, 
with the high-tension type, the cables are so short and so direct that 
the fault is likely to lie in the magneto itself. 

Q. Where would be the most likely places to look for the 
cause of failure of a dual magneto to operate? 

A. In about the order of their liability to occur, these would 
be as follows: broken or faulty connection at one of the coil terminals; 
primary or secondary cable, connecting magneto with coil, grounded 
through chafing or from being soaked with oil and water; ground 
between the dry cells and the metal battery box (this last is a not 
infrequent ground and is very annoying to locate, as it will occur 
one moment and disappear the next, owing to the vibration breaking 
the contact); dirt, oil, or excessive wear at the primary collector 
brush, and similar conditions at the brush which conveys the high- 
tension current from the coil to the distributor; failure of the coil 
through breakdown; failure of the condenser, causing the interrupter 
points to burn away rapidly; a break in the armature winding. All 
of these last are rare causes of trouble 

Q. How are these faults best remedied ? 

A. Poor connections at the coil termimals can be overcome bv 
baring about an inch and a half of the cable of insulation, twisting 
a J-inch loop in the end, and, after cleaning and wetting the 
braided end with soldering flux, dipping the loop into molten solder. 
The terminal nuts can be screwed down hard on these loops without 
opening or injuring the stranded wires, and they will make solid and 
permanent terminals. Where cables have become so oil soaked 
that the integrity of their insulation is suspected, they should be 
replaced, and the new wires properly supported. If either of the 
brushes is at fault, due to excess of oil and dirt, clean with gasoline, 
and true up the ends square with a fine file. Should the brushes 
have worn unevenly, or, in the case of the primary brush, taken on 
a hard, glazed surface, treatment with the fine file will remedy the 
trouble. When they have worn down to a point where the spring 
no longer holds them in good contact, new brushes and springs 
(attached) should be inserted. 

Q. When examination shows no fault at any of these points, 
how can the coil be tested? 


208 


ELECTRICAL EQUIPMENT 


A. Disconnect the coil from the magneto, and connect to the 
battery terminal one wire from a spare battery of four dry cells or, 
if more convenient, to an ignition storage battery. Fasten the 
ground connection from the coil to some handy metal part of the 
chassis; lay the secondary cable from the coil on the chassis so that 
its bared end is not more than J inch from the metal of the motor, 
or chassis. Then connect another length of wire to the opposite 
terminal of the testing battery. (The dry cells should be in series.) 
Scrape the end of this wire clean, and touch it rapidly to some part 
of the motor. A spark should occur every time it is touched, showing 
that the primary winding of the coil is uninjured, and, if the second¬ 
ary is likewise uninjured, a spark should jump between the bared 
end of the secondary cable and the adjacent metal, every time the 
circuit is closed with the testing wire. The occurrence of these two 
sparks show the coil to be in proper working condition. If the spark 
occurs at the testing wire, but no high-tension spark takes place at 
the end of the secondary cable, it indicates that the secondary 
winding of the coil has broken down. Should the spark, taking place 
every time the testing wire is touched to a part of the motor, be very 
bright and hot, it is quite likely that the condenser has become 
punctured. Unless the failure of the secondary is due to a broken 
connection between the fine wire of the winding and the terminal, it 
must be sent to the maker for repairs. This is the case also when the 
condenser has been punctured. The magneto will continue to work 
with the condenser short-circuited, but this will cause a rapid burn¬ 
ing away of the expensive platinum contact points of the interrupter. 

Q. How is the magneto armature winding tested for a break? 

A. Employ the test battery already mentioned. Touch one 
wire to the armature shaft, and the other to the collector end which 
is insulated from the shaft. A spark should result if the winding is 
intact. Failure to obtain a spark would indicate a break in the 
winding, and the armature should be returned to the maker for 
repairs. In making tests with a battery in this manner, always 
make sure that the connections from the battery have not pulled 
loose nor become broken, before finally accepting the lack of a spark, 
at the point where it should occur as conclusive evidence of a fault 
in the part being tested. Otherwise, a failure of the testing apparatus 
itself may be put down as a fault in the part being tested. 


ELECTRICAL EQUIPMENT 


209 


Q. Is a spark the best indication obtainable in making such 
tests? 

A. With a fresh battery of dry cells, the self-induction of the 
coils tested, such as the winding of the armature or the primary of 
the coil, will give a bright spark that cannot be mistaken; but, if an 
audible indication be desired, the battery may be placed in a box and 
a common electric door bell, or buzzer, mounted on the box. The 
bell, or buzzer, must be connected in series with the testing wires, 
so that, when the circuit is completed, the current passes through it. 
Then the success of the test will be evidenced by the sounding of 
the bell, or buzzer, as long as the circuit is closed. In the case of 
the secondary winding of the coil, the spark is all that is necessary. 
Should a more visible signal be desired, the lamp-testing set, described 
in connection with trouble hunting on the starting and lighting 
system, may be employed. In this case; the test battery is dispensed 
with and the 110-volt lighting circuit used, but a 10-ampere fuse- 
block and fuses should be inserted in the testing circuit to guard 
against accidental short-circuits in handling the testing apparatus. 

Q. As secondary cable is expensive, and the owner does not 
usually want it replaced unless absolutely necessary, how can it be 
tested for faults? 

A. Connect the test battery to the coil, as previously described, 
but, instead of relying upon breaking the circuit by hand, insert a 
buzzer, or bell, in series, between the battery and the primary of 
the coil. This will give a vibrating contact, and will keep the coil 
working continuously. Connect the piece of cable to be tested to 
the secondary of the coil and support it well, clear of the ground, such 
as the motor or chassis. Take another piece of secondary cable and 
connect one end of it to the ground. Bare the other end, and pass 
this along the entire length of the cable being tested, very close to, 
or actually touching, the insulation of the cable under test. If there 
are any weak spots in the insulation, a spark will jump through it 
to the testing wire. In case a vibrating coil is at hand for making 
this test, it will not be necessary to insert the buzzer as mentioned. 

Q. What is likely to result when there are weak spots in the 
insulation of the secondary cables? 

A. The high-tension current will escape through them to the 
ground, because of the nearness or actual contact of the secondary 


210 


ELECTRICAL EQUIPMENT 


cable with the motor cylinders or other metal parts. This leakage 
will be neither visible nor audible, unless the insulation is very bad, 
and the failure to fire will usually be attributed to the spark plug 
instead. 

Q. Should primary cables be tested in the same manner. 

A. It is not necessary; as, unless the insulation is actually worn 
off, there will be no escape of current, owing to its low voltage. 
Where solid instead of flexible primary wire is employed, as on some 
old cars, or where the owner has made replacements, a test for a 
break in the wire itself under the insulation may be made with the 
aid of the battery and buzzer alone. 

Q. Are the causes of failure similar in a true high=tension 
magneto? 

A. No. As the primary-generating winding and the secondary, 
or high-tension winding, are both on the armature of the magneto 
itself, and all connections, except the high-tension leads from the 
distributor to the spark plugs, are made internally, there are no out¬ 
side cables, terminals, or coils to default. Unless the repair man has 
become proficient in testing electrical apparatus and has familiarized 
himself with the construction of the high-tension type, he will find it 
preferable to refer to the manufacturer any cases of trouble in this 
class of apparatus. In fact, the maker usually absolves himself from 
any responsibility in case a magneto of this type has been taken 
apart. Even where the repair man is capable of dismantling and 
testing this type of magneto, its repair would ordinarily be beyond 
his facilities, so that it is better to refer it to the maker at once. 

Q. Are there any faults, peculiar to the “duplex’’ or to the 
“double=spark” types of magnetos, which are not encountered in 
the others? 

A. In the case of the duplex type, there may be a failure to 
work of the battery connections or of the battery commutator on 
the armature shaft, i.e., the commutator which throws the battery 
current into phase with the armature current of the magneto when 
starting. Since the advent of the self-starter, this type of magneto 
has had no particular advantage to recommend it, and will be found 
only on older cars. As the only difference between the double-spark 
and the usual magneto is a duplication of the distributor to give two 
sparks in the cylinder instead of one, its treatment is the same. 


ELECTIUCAL EQUIPMENT 


211 


There are simply two distributors to maintain instead of one. This 
type is also of limited application and will be found only on com¬ 
paratively few cars of several years back. 

Q. Why is it important that the magneto be accurately timed? 

A. Unless the spark occurs at exactly the right moment, the 
motor will not operate efficiently. If it occurs too soon, the explosion 
will tend to retard the piston; if too late most of the power that 
would have been derived from the compression will be lost. As the 
lag, i.e., the time intervening between the moment the contact 
points are opened at the interrupter and the occurrence of the spark 
at the plug, is negligible in the magneto, it must be more accurately 
timed than the old battery and vibrator-coil system. 

Q. Does the magneto ever fail to operate through lack of oil, 
and what attention should be given to its lubrication? 

A. Prior to 1910, when some of the lower-priced magnetos were 
made with plain bearings, this naturally occurred, but, with the 
adoption of high-grade annular ball bearings for the magneto shaft, 
it is practically unknown. However, even the high-grade ball bear¬ 
ing will not operate without lubrication. If it runs dry, the balls 
are apt to rust and ruin the bearing. Most of these bearings are 
packed with vaseline, or similar light grease, when the machine is 
assembled and require no attention during the life of the average 
car. Where this has not been done, as on some of the older machines, 
a few drops of fine sewing-machine oil once a year will suffice. The 
pivot and roller of the contact-breaker arm also should be oiled once 
or twice a year with one drop of oil to each, using a toothpick. 

Q. When taking a magneto apart, as where it is necessary to 
remagnetize the fields, why is it of the greatest importance to 
reassemble them in the same way? 

A. Unless this is done, the polarity of the fields will be reversed 
and the machine will not generate properly. The maker usually 
identifies the polarity of the fields by marking the magnets so that it 
is easy to reassemble them in the proper manner. See the illustra¬ 
tion of the Eisemann magneto. Fig 103. 

Q. When remagnetizing the field magnets of a magneto, why 
is it important that their polarity should not be changed in the 
process? 

A. The effect would be exactly the same as if the remagnetizing 


212 


ELECTRICAL EQUIPMENT 


were carried out properly, so far as their polarity were concerned, and 
then the magnets were put back the wrong way. The machine 
would not generate. For example, the marking on the side of the 
Eisemann magneto indicates the north pole of its fields. If in 
remagnetizing, this side of the field is made the south pole, and it 
is then correctly assembled, it will be evident that the polarity of 
the entire field has been reversed. 

Q. In the case of the dual magneto, how can trouble, caused 
by the grounding of the dry cells against the metal battery box, be 
overcome? 

A. By making a tight-fitting wooden box to hold the battery, 
this wooden box fitting inside the metal one. 

Q. Does the care required by an inductor type of magneto 
vary from that necessary for other types? 

A. No. So far as its outside connections go, it is the same. 
That is, in a dual type installation, using an external coil, or trans¬ 
former, the causes of trouble and their remedies will be the same as 
in any dual system, as already given; and this also applies to the 
high-tension dual type. 

Q. In the order of their occurrence, what are the commoner 
causes of failure of the magneto, due to wear of its parts? 

A. In practically every case of failure of the magneto that is 
not otherwise apparent at a glance, an inspection should always be 
made of the contact points in the breaker box. Unless they open 
properly when the cam strikes the lifter, no current reaches the out¬ 
side circuit and the coil is not energized. Next, inspect the contact 
of the collector brush; see that it is clean; that it is making good 
contact over its entire surface; and that its spring is holding it firmly 
in place. After this, inspect the distributor. 

Q. How often should the contact points in the breaker box 
require attention? 

A. This will depend upon the type of magneto, and when it 
was made. On some of the earlier types, prior to 1909, no condensers 
were used on many of the lower-priced magnetos, and the points 
required attention every 3,000 or 4,000 miles. Others will run two 
or three times this distance without requiring attention. If, when 
the points have been found in poor condition, they have not been 
properly trued up and adjusted, they are apt to require attention 


ELECTRICAL EQUIPMENT 


213 


again much sooner, as any irregularities in their contact faces will 
cause them to burn away much more rapidly. 

Q. As the platinum contacts of the magneto breaker box are 
expensive, how far down can they be allowed to wear before it is 
necessary to replace them? 

A. This will depend upon the amount of adjustment provided. 
As long as there is sufficient platinum left to provide a true surface 
on each contact point, it Vv^ill not be necessary to replace them if 
they can be adjusted so that the cam opens and closes them properly. 

Q. Since the magneto=armature circuit is normally closed 
upon itself and only opens when a spark is required at one of the 
plugs, how is the magneto ignition shut off? 

A. By short-circuiting the armature around the contact points. 
Instead of opening the entire ignition circuit, as in the case of a battery 
where it is necessary to save current, the generating part of the 
circuit is closed. This is true of all high-tension magnetos. 

Q. When the contact points of the interrupter of the magneto 
fail to separate, what is the result? 

A. The armature remains short-circuited upon itself through¬ 
out the revolution, and no current reaches the outer circuit, so that 
the engine will not fire on the magneto at all. 

Q. What is the result when the contacts open but the gap is 
not wide enough? 

A. Erratic missing, probably at all speeds, but more pro¬ 
nounced when the engine is running slowdy. The increased kick 
given the movable contact arm by the cam, when the engine is run¬ 
ning at a higher speed will cause it to fire more regularly. 

Q. What happens when contact points are separated too far? 

A. The missing is likely to be more noticeable at high speeds 
than at low speeds; as, when turning very fast, the looseness of the 
movable contact arm may prevent it from closing the circuit again 
in time for the next cylinder to fire. 

Q. What is the proper distance for the setting of the contact 
points of the magneto interrupter, or breaker box? 

A. Approximately A inch, or the equivalent of an ordinary 
sheet of paper. When the points are properly adjusted, it should 
be possible to insert the paper between them and move it around 
without binding. 


214 


ELECTRICAL EQUIPMENT 


Q. How are the contact points usually adjusted? 

A. Practically every magneto manufacturer now supplies an 
adjustment gage, which serves also as a screwdriver or small spanner, 
according to the construction of the interrupter. The thickness of 
the metal represents the distance that the contacts should open. 
In all except the old types produced several years ago, the interrupter 
may be removed without the use of any tools, and the adjustment 

made without the neeessity of 
removing the magneto from its 
bedplate. The following instruc¬ 
tions cover the Eisemann dual 
type in this respect, and are typi¬ 
cal: “Insert from behind through 
the hole in the plate earrying the 
make-and-break mechanism, the 
metal adjuster which we supply 
with every magneto: by means 
of a flat wreneh hold the nut 
on platinum screw (contact) and 
turn the platinum serew upward 
or downward until there is a gap 
of A inch between the eontacts, 
i.e., a piece of paper must pass between them without getting 
jammed”. Fig. 143. 

Q. How often should the magnets of a magneto need remag= 
netizing? 



Fig. 143. 


Method of Adjusting Magneto 
Contact Points 


A. No definite time nor average can be given for this. In 
some eases, the makers state specifically that the magnets will never 
need remagnetizing during the entire life of the machine, unless they 
are taken off and allowed to stand without a “keeper”, i.e., a piece 
of soft iron placed across the pole pieces, the magnets themselves 
being placed in their usual relation as when on the machine. In 
others, it has been nothing unusual to require this onee a year, or 
after 6,000 to 10,000 miles running. 

Q. How can it be determined definitely whether the magnets 
actually need remagnetizing or not? 

A. Many cases of weak or faulty ignition are attributed to 
loss of strength in the magnets, when they are actually due to some- 










ELECTRICAL EQUIPMENT 


215 


thing else. Before deciding that the magnets themselves are at fault, 
every part of the system should be gone over thoroughly. See that 
the contact points are clean and true, and that they are properly 
adjusted; that the low-tension collecting brush, or contact, is clean 
and is making good contact; also, that the distributor is clean. 
Inspect all terminals and connections. Test the condenser. Dis¬ 
connect one of the spark-plug leads, keep it away from any metal 
part of the chassis and, with the engine running, note whether a 
spark occurs at the safety gap. In a high-tension magneto, this gap 
is ually located in the hollow of the magnets back of the distributor; 
in a low-tension type, having a separate coil, it is usually on the coil. 
Take the spark-plug lead which has been detached (engine running) 
and approach its metal terminal gradually to the spark-plug end, or 
to some metal part of the engine, noting the maximum distance that 
the spark will bridge. If this is one-quarter inch or more, the mag¬ 
nets are not at fault. 

Q. When there is no question but that the magnets are the 
cause of faulty ignition, how can the magnets be remagnetized? 

A. With the aid of a small electromagnet, as described in the 
chapter on this subject. Care must be taken to see that the polarity 
of the magnets is not reversed in the process, as this will render the 
magneto altogether inoperative. 

Q. How is the ground connection made in a magneto? > 

A. One side of the winding of the armature in a low-tension 
type, and of both windings, i.e., the primary and secondary are 
grounded by being electrically connected directly to the core of 
the armature itself, in the high-tension type. The fastening of the 
magneto in its bedplate on the engine, completes this ground con¬ 
nection. __ 

Q. Is it ever advisable to insert paper liners, or liners of any 
material, between the magneto and its bedplate? ^ 

A. If on an old car, it is necessary to resort to liners or shims 
to correct the alignment of the magneto with its driving shaft, 
nothing but thin sheets of brass or iron should ever be employed, as 
the use of any insulating material for this purpose would break the 
ground connection and prevent the magneto from functioning 
properly. But even on old cars, where the lack of alignment of the 
magneto with its shaft is such as to be plainly perceptible to the 


210 


ELECTRICAL ICQUIPMENT 


unaided eye, the Oldham coupling usually employed on the driving 
shaft, allows sufficient play to compensate for this. Any lack of 
alignment is more likely to be due to carelessness in replacing the 
magneto after it has been removed from the engine for attention, 
than to any fault in the placing of the bedplate and driving shaft. 

Q. What will be the result of the magneto being lined up 
incorrectly? 

A. The universal coupling is apt to wear badly, and the side 
pressure, which the lack of alignment causes, may not be taken care 
of entirely by the coupling, so that the pressure has to be taken in 
part by the magneto shaft and its bearing. This will result in undue 
wear of the bearing and, in time, may permit the armature core of 
the magneto to strike the pole pieces, or sides of the tunnel, so that 
it will jam. On many of the higher-priced cars, a flexible coupling, 
consisting of leather discs, is employed for the magneto drive. 

Q. Which is more likely to occur, separation of the points by 
too great a distance or their coming together so that they do not open? 

A. The result of wear will usually be to increase the distance 
between the points, but the writer has experienced the opposite on 
an old car where the cam apparently wore down faster than the points 
and prevented their opening. This was probably due to improper 
hardening of the cam itself or to the fact that the roller was harder 
than the cam. Many of the later models do not employ a roller in 
the movable contact arm, the cam striking directly against a pro¬ 
jection on the arm itself (see Eisemann interrupter. Fig. 143). An 
example of the roller type, is the K-W interrupter. Fig 69. 

Q. Is it possible for the adjustment of the contact points to 
wear to such a degree that the magneto will fire the engine at high 
speeds, but not at all at low speeds? 

A. Instances of this nature on old magnetos have proved a 
puzzling cause of ignition failure. The extra kick of the cam at 
high speeds would separate the points, whereas at low speeds they 
remained together. 

Q. Inspection having shown other parts of the ignition system 
to be in good order, how can it be determined whether the magneto 
itself is at fault? 

A. Run the engine on the battery, and switch from battery to 
magneto while the engine is running at a good speed. If the magneto 


ELECTRICAL EQUIPMENT 


217 


is not operating properly, the difference in running will be perceptible 
immediately; in case the contact points are not opening, the explosions 
will cease at once upon throwing the switch to “magneto”. 

Q. What is meant by “ignition timing”? 

A. A four-cycle motor is so-called because there are four parts 
to each cycle: viz, suction, compression, firing, exhaust. It is 
evident that ignition is necessary only at one part of the cycle and 
that the spark must occur at a certain time with relation to the 
carrying out of that part of the cycle. Determining the point at 
which the spark is to occur in that part of the cycle is usually referred 
to as the “timing of the spark”, or as the “ignition timing”. 

Q. Is it necessary that this be carried out with precision? 

A. In the high-speed automobile motors of the present day, it 
must be extremely accurate with relation to the movement of the 
piston and must be exceedingly rapid in action; otherwise, the 
efficiency of the motor would suffer greatly. In the slower-running 
motors with fewer cylinders, of several years ago, neither of these 
factors was of such great importance; but the present-day high-speed 
multi-cylinder motors could never be operated satisfactorily on 
ignition apparatus of the type familiar on 1910 models, for example. 

Q. Why would a variation or a lack of precision affect the 
running of the motor? 

A. Speeds are now so high that the time factor is reduced to 
exceedingly small fractions of seconds. For example, take a high-speed 
four. It turns at 2500 r.p.m.: as there are two explosions per revolu¬ 
tion in a four-cylinder motor, this would mean 5000 sparks per 
minute, or one spark every .012 second. This is cutting time pretty 
fine, but in a modern twelve-cylinder motor, it is finer still. Say the 
twelve runs at 3000 r.p.m.: in a twelve there would be six explosions 
per revolution, requiring 18,000 sparks per minute, or one for every 
.0033 second—thirty-three ten-thousandths of a second—an 
incredibly brief space of time in which to carry out a combined 
mechanical and electrical function. 

Q. How is this extreme accuracy obtained? 

A. By the use of precision machine work in the distributor, 
approaching that of a fine watch, and a great amount of “advance” 
to compensate for any lag in either the mechanical or electrical 
functioning of the apparatus. 


218 


ELECTRICAL EQUIPMENT 


Q. What is meant by “lag’’, and what is the difference between 
mechanical and electrical “lag”? 

A. As the term implies, lag is delay: in other words, it is the 
time elapsing between the moment a part begins to move and the 
actual moment at which it moves and makes contact or carries out 
the function for which it is designed. Mechanical lag is due 
entirely to the time necessary to overcome the inertia either of a part 
that is stationary or of one that is moving in another direction and 
whose direction must be reversed. Electrical lag, on the other hand, 
is the time elapsing between the moment that current is switched 
into a piece of electrical apparatus and the moment that the apparatus 
actually operates. This will appear strange at first sight in view of 
the universal belief that anything electrical operates so swiftly that 
it is next to impossible to measure the time required. This is true 
when nothing more than the passing of a current of electricity from 
one point to another is concerned, but when actual work must be 
performed by the current, the time required is not only measurable 
but it may be so perceptible as to have a decided effect upon such 
extremely rapid functioning as that mentioned. For example, 
when the work to be performed by the current consists of magnetizing 
the core of a coil, as is necessary in automobile ignition, the time 
element is quite perceptible, as may be noted by referring to the 
oscillograph of the spark produced by an induction coil. Fig. 95. A 
coil having the characteristics shown by this oscillograph would be 
worthless on a modern high-speed motor. 

Q. How is this lag compensated for? 

A. By advancing the moment that contact is made outside of 
the cylinder to an extent that will insure the occurrence of the spark 
in the cylinder at the proper moment. In other words, the current 
is started on its way sooner with relation to the movement of the 
piston. This is generally referred to as “advancing the spark”. 

Q. What is the proper point, in the travel of the piston on the 
compression stroke, for the ignition spark to occur? 

A. Exactly at the upper dead center just before the piston 
starts downward again. The compression is then at its maximum, 
and firing the charge exactly at that moment results in the production 
of the greatest amount of power. The compression falls off very 
rapidly the moment the piston starts down on the power stroke, so 


ELECTRICAL EQUIPMENT 


219 


that ill a high-speed motor, the loss of even a very minute fraction 
of a second causes a considerable loss of energy. 

Q. What will happen if it occurs too soon? 

A. This will depend largely upon the type of motor and upon 
how much in advance of the proper time it actually occurs. In a 
slow-speed type running well below its normal r.p.m. rate, as where 
a motor with a normal speed of 1000 r.p.m. is slowed down to 600 
r.p.m., owing to climbing a hill, advancing the spark to its maximum 
will cause hammering or pounding in the cylinders, indicating that 
the explosion is taking place before the piston reaches upper dead 
center and, consequently, that most of its energy is being expended 
against the rising piston, instead of helping thrust it downward as it 
should. When running at its normal rate, the piston speed of such 
a moior would be sufficient for the piston to have reached upper 
dead center before the burning gases had time to expand, so that their 
entire output of energy would be expended in producing power. In 
high-speed multi-cylinder motors with their diminutive cylinders 
and light moving parts, the piston speed is so great that even the 
maximum advance in the ignition timing would have no effect, 
even as the lowest speed of which the motor is capable. 

Q. What is the result when the spark occurs too late? 

A. The piston has already started on its downward stroke; 
the point of maximum compression has been passed, so that the full 
benefit of the compression is lost, and with it, a large part of the 
energy that would otherwise have been utilized. 

Q. Has running with a late spark any other effect on the 
motor? 

A. Yes. The gas in the combustion chamber is ignited so late 
that it continues to burn after the exhaust valve is opened. As the 
heat units it contains are not utilized as power, they are retained 
longer in the cylinder in the form of heat; the water jackets are 
compelled to absorb 50 per cent more of the heat than they should; 
and the whole motor is said to “run hot” or to “overheat”. The late 
combustion of the gases does not permit of sufficient time for the 
normal amount of heat to escape by way of the exhaust, so that there 
is still burning gas in the combustion chamber when the exhaust 
valve closes. 

Q. What other term is used in referring to a late spark? 


220 


ELF.CTRICAL EQUIPMENT 


A. Retarded ignition, or a retarded spark, meaning one that 
occurs later in the firing part of the cycle, i.e., later with relation to 
the travel of the piston itself. An early spark, or advanced spark, is 
set to occur or rather start to take place well before the piston has 
reached upper dead center on the compression stroke. The time ol 
ignition is always based on its relation to the position of the piston, 
though frequently referred to in terms of degrees on the periphery of 
the flywheel. This is done for greater convenience in setting the 
ignition, as the timing of the valves is always marked on the rim of 
the flywheel. 

Q. Why is it necessary to have the ignition occur later at one 
time than at another? 

A. To permit of starting the motor; especially by hand. The 
time of ignition is advanced to compensate for the extremely rapid 
travel of the piston, and is designed to cause the spark to take place 
just as the piston reaches upper dead center on the compression 
stroke. In high-speed motors this advance amounts to as much as 
1 inch of the stroke. It will, accordingly, be evident that if an 
attempt be made to start the motor with the spark advanced, igni¬ 
tion will take place before the piston reaches upper dead center and 
the motor will kick back. 

Q. How much allowance is usually made for retarding the 
time of ignition? 

A. In the ordinary type of motor in which the speed does not 
exceed 1500 to 1800 r.p.m., it is customary to have the latest timing 
allowed coincide with the upper dead center position of the piston. 
In some cases, the spark may be retarded to take place after the 
piston has traveled a short distance down on the firing stroke, or 
about 5 degrees to 7 degrees on the rim of the flywheel. In the 
majority of cases, however, “extreme retard” is at the upper dead 
center of the piston. 

Q. How is the time of ignition, or “spark”, advanced and 
retarded? 

A. The timer, in the case of a system using vibrator coils, and 
the distributor, in all systems using one vibratorless coil, consists of 
two parts. In the case of the timer, the four contacts for a four- 
cylinder motor are set into the inner periphery of a circular casing 
and a single revolving contact, mounted on the camshaft, passes 


ELECTRICAL EQUIPMENT 


221 


over them consecutively, sending the current through the primary 
winding of each of the induction coils in rotation. These coils are 
connected to the spark plugs of the different cylinders in the proper 
firing order. While this outer casing of the timer is normally sta¬ 
tionary, it may be moved part of a revolution with relation to the posi¬ 
tion of the revolving contact. For example, if the moving member 
in its revolution were within 20 degrees of touching the contact 
corresponding to coil and cylinder No. 1, and then the casing were 
revolved 20 degrees in the same direction as that in which the con¬ 
tact is moving, it will be evident that the meeting, or contact, of the 
two will take place that much later, and the occurrence of the spark 
in the cylinder will be correspondingly delayed. If, instead of being 
moved away from the revolving contact, the housing is revolved 
against the direction of rotation of the contact, the two will come 
together that much sooner and the spark will be advanced, or occur 
earlier. This housing of the timer is connected by means of linkage 
with the spark lever under the steering wheel. 

In the case of the distributor, the principle is exactly the same, 
except that the current is sent in turn by each one of the contacts, 
through the same induction coil, instead of having a coil for each 
cylinder. The method of accomplishing this result is also varied: 
in many magnetos the distributor consists of a revolving block 
carrying a single contact, while a carbon brush for each cylinder 
bears against it. In most of the battery-system distributors, the 
arrangement is very similar to a timer, but the construction and 
insulation are naturally carried out in very much better fashion. 

Q. What is meant by an advance of 30 degrees for the ignition? 

A. That the difference between the point of extreme retard, 
usually upper dead center of the piston, and that of maximum 
advance or earliest ignition for high speed, represents 30 degrees on 
the flywheel. Just what this corresponds to in distance traveled 
by the piston naturally depends entirely upon the diameter of the 
flvwheel. 

Q. What is meant by the magneto setting point? 

A. This is a line inscribed on the flywheel in the same manner 
as the usual marks for the valve timing of the motor. There is a 
corresponding dead line, or pointer, on the crankcase, with which 
these lines on the flywheel are registered to check the valve timing 


222 


ELECTRICAL EQUIPMENT 


and the setting of the magneto. When the magneto-setting lines on 
the flywheel is directly opposite the dead line, or pointer, on the 
crankcase, the piston of cylinder No. 1 should be at upper dead 
center exactly on the compression stroke, i.e., on the previous down 
stroke, it has drawn in a fresh charge, and when the piston again 
reaches upper dead center it has completed compressing this charge, 
so that the cylinder is then ready to fire. With the piston of this 
cylinder at the position in question, the contact points in the breaker 
box of the magneto should be just opening. 

Q. How is the ignition timing advanced or retarded on a 
magneto? 

A. The magneto breaker box may be moved part of a revolu¬ 
tion, with relation to the contact points, in exactly the same manner 
as previously described for a timer or distributor. This alters the 
relation of the cam which opens the contact points to the latter so 
that their separation takes place earlier or later, in accordance with 
the direction the breaker box is rotated. 

Q. Why is it that a motor may be cranked by hand with the 
spark lever in the fully advanced position when starting on the 
magneto, and why can this not be done safely with a battery? 

A. There is less actual advance in the time of ignition, as 
supplied by the magneto, represented by the movement of the 
spark lever. That is, moving the spark-advance lever to its maxi¬ 
mum does not cause so much advance in the actual timing of the 
ignition when connected to the magneto for starting, as it does when 
connected to the battery. The speed of the magneto itself is 
responsible for a considerable advance in firing time when the motor 
is running, whereas the battery ignition has a fixed speed of operation, 
regardless of whether the motor is being turned over by hand or is 
being run full speed. Moreover, as the usual magneto setting point 
is upper dead center, the spark does not actually occur until slightly 
later, when the motor- is being cranked slowly, so that, while the 
spark lever may be in the advanced position, the actual occurrence 
of the spark is not perceptibly earlier than it would be with the lever 
fully retarded. This makes it possible to crank the motor with the 
lever fully advanced on the magneto, without any danger of a back¬ 
fire. This is not true to the same extent with the Ford magneto as 
with other types, owing to the great number of pole .pieces and anna- 


ELECTRICAL EQUIPMENT 


223 


ture coils that it carries. With a battery, however, the occurrence 
of the spark is just as rapid at low speeds as at high, so that attempt¬ 
ing to start on the battery with the lever fully advanced will 
invariably result in a vicious back kick; the whole force of the explo¬ 
sion is exerted against the rising piston. As there is a greater amount 
of lag in the ordinary battery system than there is with the magneto 
the movement of the spark lever represents more actual advance, as 
this is necessary to provide for the time lost in the operation of the 
system. This, however, applies only to old battery systems, such as 
the dry cells used in connection with the magneto in a dual systems 
and not so much so to the so-called modern battery-ignition systems 
which are practically as rapid as the magneto. 

Q. What is meant by fixed ignition? 

A. The time of ignition is not variable by means of a spark- 
advance lever. Only a magneto is employed (true high-tension 
type) for ignition and it is set to fire at the maximum advance at all 
times when running. Provision is usually made for retarding the 
time of ignition to allow for hand starting, though this is not always 
the case, as it is not absolutely necessary (see answer to previous 
question). Otherwise, the ignition is always advanced to the maxi¬ 
mum and there is no lever on the steering wheel for varying it. This 
type of ignition system has been very generally employed abroad 
and, more particularly in France, on commercial vehicles, such as 
cabs, but has never found any favor here. It has not been used in 
this country, except on a very few makes of cars, and then only for 
the models of one or two seasons, the latest being about 1912. 

Q. What is meant by automatically advanced ignition, and 
how is this accomplished? 

A. Instead of relying upon a manually operated spark lever 
under the steering wheel, a centrifugally operated device is incor- 
})orated with the timer or distributor. As this depends upon the 
speed of the motor for its operation, the ignition timing is always at 
the point of extreme retard when the motor is stopped, so that it may 
be cranked by hand without taking any precautions to retard the 
spark. The device is practically a small centrifugal governor the 
weights of which expand against the action of a spring under the 
influence of increasing speed. These weights are connected by a 
lever to the tinier, or distributor housing, so that, as they expand 


224 


ELECTRICAL EQUIPMENT 


with increasing speed, they move the housing in the proper direction 
to advance the time of ignition. The spring automatically returns 
the housing to the retarded position when the motor slows down or 
stops. The automatic-advance device is a feature of the Atwater 
Kent battery system, and is also employed on one of the types of 
Eisemann magnetos particularly designed for use on commercial 
vehicles. It relieves the driver of the necessity of giving any atten¬ 
tion to this part of the control, as the time of ignition is always pro¬ 
portioned exactly to the speed. 

Q. When all other factors are fully up to requirements, such 
as proper carburetion, valves recently ground, spark=plug points not 
too far apart, and property fitting pistons, but the motor fails to 
operate with the same “snap” and power it delivered when newer, 
what is likely to be the cause? 

A. Wear in the linkage connecting the spark-advance lever 
with the timer, the breaker box of the magneto, or the distributor of 
a modern battery system, is responsible for so much lost motion that 
the full movement of the spark-advance lever is no longer being 
transmitted to the ignition apparatus. In other words, the full 
advance of the spark lever on the steering wheel no longer represents 
the maximum advance at the timer or distributor, so that the motor 
is not firing as early as it should and a considerable percentage of 
the energy, represented by exploding a fully compressed charge, is 
being wasted. The effect is the same as loss of compression from any 
other cause. 

Q. When the motor will run slowly at one moment and then 
speed up to the racing point without any apparent cause, then drop 
off again to slow speed, what is likely to be the cause? 

A. Unless this is directly traceable to a partially clogged car¬ 
buretor jet or a loose throttle which is jogged open and closed by the 
vibration, the wear mentioned above may be responsible. The 
spark-advance linkage has become so loose through wear that it no 
longer holds the timer or distributor at the point to which the lever 
is moved on the quadrant on the steering wheel, and the vibration 
of the motor moves it back and forth, advancing it at one moment 
and retarding it the next. 

Q. When the motor does not respond at all to the movement 
of the spark=advance lever, what is the trouble? 


ELECTRICAL EQUIPMENT 


225 


A. There is an aetiial break between the lever on the steering 
wheel and the timer, or distributor, or the breaker box of the magneto. 
This is apt to leave the ignition timing fully advanced, making it 
dangerous to attempt to start the motor by cranking it on the 
battery. 

Q. Why do some motors require a greater amount of ignition 
advance than others? 

A. Because of their greater speed or the increased amount of 
lag in the ignition system which must be compensated for by the 
timing. 

Q. What system of ignition has the greatest amount of lag, 
and which the least? 

A. The old battery system, using a roller-contact timer and 
vibration coils, has the maximum amount of lag, as there is both a 
mechanical and an electrical lag. The high-tension magneto and 
the modern battery system are great improvements in this respect, 
and there is not much choice between them on this point. As an 
illustration of the eflPect of the motor speed on the amount of advance 
required, the Packard “twin-six”, using a modern battery system, 
requires as much advance as the old Packard “four”, on which a 
low-tension magneto was employed; while the Packard six-cylinder 
motor, which was fitted with a high-tension magneto, required con¬ 
siderably less than either of these. 

Q. Why is it necessary in some ignition systems to set the 
spark “late”, or after the piston has actually started downward on 
the firing stroke, when the spark lever is at the point of maximum 
retard, while in others it is only necessary to set it at upper dead 
center? 

A. This is due to the difference in the amount of lag, and also 
to whether a battery or a magneto is employed. It is necessary to 
insure safety in hand cranking, as, where the lag is reduced to the 
minimum, the explosion would take place before the piston had 
reached a point where it could start downward on the firing stroke, 
and a back kick would result. 

Q. Is the piston actually at upper dead center for ignition= 
setting purposes when it has ceased to rise? 

A. No. There is an interval in the revolution of the crank 
during which the piston does not move, i.e., while the crank is moving 


22G 


ELECTRICAL EQUIPMENT 


in practically a horizontal plane, and it should complete this part of 
the revolution, so that the piston is just on the point of starting 
downward again before it reaches the proper point for ignition set¬ 
ting at maximum retard. 

Q. What is meant by “fixed” ignition? 

A. This refers to those systems in which there is no provision 
made for altering the time of ignition, either by a manually operated 
lever on the steering wheel, or by an automatic device for advancing 
and retarding it. In other words, the time of ignition is fixed and 
is always the same, regardless of the speed of the motor. It can be 
used only in connection with a magneto. ■ 

Q. What is the ignition=setting point for “fixed” spark? 

A. This represents a mean between what would be the points 
of maximum retard and maximum advance in a variable system. 
The spark must not occur too late as the motor will develop only a 
percentage of its power and will overheat; nor must it be too early, 
as the motor is then apt to fire against the rising pistons when slowed 
down, as in climbing a hill or when heavily loaded. The magneto 
must be set, therefore, so that the spark occurs before the piston 
reaches upper dead center. Just how much in advance of that 
point the setting should be, will depend upon the motor itself. As 
will be noted in the table of firing orders, a much greater range of 
timing is allowed for on some motors than on others, so that there is 
no rule which will apply to all. The ignition-setting point as given 
by the manufacturer should be learned and the magneto set in 
accordance. 

Q. Is fixed spark ignition in common use on American cars? 

A. Although very largely used abroad, particularly in France, 
on commercial vehicles such as taxicabs, it has never found favor 
here and will be found on very few cars. 

Q. Is there any other method of checking the ignition=setting 
point besides the marks on the flywheel or the position of the piston 
of one cylinder in its relation to the contacts of the interrupter? 

A. In some magnetos, such as the Eisemann, there is a set¬ 
ting mark on the distributor of the magneto. When the piston is in 
the proper position for firing, it is only necessary to bring this setting 
mark in line with a setting screw on the stationary part of the 
distributor. 



ELECTRICAL EQUIPMENT 


227 


Q. Why do the cylinders of an automobile engine not fire 
consecutively? 

A. Because the pistons are attached to the crankshaft in 
pairs in the same plane, so that when one piston of a pair is firing 
the other one is going down on the exhaust stroke. 

Q. How can the firing order of a motor be determined? 

A. Take out all the plugs and lay them on the cylinders so 
that the threaded part of the plug makes contact with the cylinder 
but the terminal does not. Switch battery on and turn engine over 
slowly, noting the order in which the sparks occur at the plugs. 
Watch the valve stems; after the inlet valve of cylinder No. I has 
opened and closed, it is ready to fire. The plug at which the spark 
then occurs is the proper plug for the first cylinder. The next plug 
to spark belongs to the cylinder whose inlet valve has just closed. 

Q. When a motor will not start, but fires once or twice and 
then stops, the flywheel rocking back and forth, what is the cause? 

A. Some of the spark-plug leads have been misplaced, so that 
after one or two explosions, the next one takes place out of sequence. 

Q. How many different firing orders are possible in a motor? 

A. This depends upon the number of pairs of cylinders in a 
motor, as the two cylinders of a pair cannot fire consecutively, so 
that the ignition alternates from one pair to another. For example, 
in a four-cylinder motor, cylinders No. 1 and No. 4 constitute one 
pair, in that they are attached to crankpins in the same plane, i.e., 
they rise and fall together; cylinders No. 2 and No. 3 constitute the 
other pair. Consequently, starting with cylinder No. 1, there are 
only two firing orders possible in a four-cylinder motor, as follows: 
1-2-4-3, or 1-3-4-2. By starting with cylinder No. 2, as the first 
to fire, two more orders may be used, as 2-1-4-3 or 2-4-3-I. It 
will be apparent, of course, that the last-named combination is merely 
the reverse of the second one given above, i.e., 1-3-4-2. In this 
way, the total number possible with a motor of this type is eight 
firing orders. 

Q. Do motors differ much in this respect, or are firing orders 
pretty well standardized? 

A. Of the eight possible firing orders that may be used in a 
four-cylinder motor, only two are in common use, viz: 1-2-4-3, 
and 1-3-4-2. This is because the selection of cylinder No. I as 


228 


ELECTRICAL EQUIPMENT 


the first to fire renders it easier to set the ignition timing, as the 
piston of the first cylinder is usually more accessible than the others. 
There are some exceptions to this, the 2-1-4-3 firing order having 
been used by one or two makes of cars for several years; but the two 
mentioned above are in such general use as to be considered practi¬ 
cally standard. 

Q. How does the firing order of a six=cylinder motor differ 
from that of a four? 

A. It is exactly the same in principle, as the six consists of 
three pairs of cylinders, the pistons of which are attached in couples 
to the crankshaft, 120 degrees apart; in other words, a three-throw 
crankshaft, instead of the two-throw of the four-cylinder motor, in 
which the cranks are 180 degrees apart. Pairs of cylinders, in this 
connection, has no reference to the manner in which they are cast, 
but refers simply to their relation to the crankshaft, which, in turn, 
affects their firing order. The ignition must accordingly alternate 
from one pair to another in exactly the same manner as in the four, 
but a greater number of combinations is possible as there are three 
pairs of cylinders. 

Q. What are some typical firing orders for six=cylinder motors? 

A. As in the case of the four-cylinder motor, the use of cylinder 
No. 1 as the starting point has been practically standardized, hence 
the firing orders in general use begin with it, as: 1-5-3-6-2-4, or 
1-4.2-6-3-5. 

Q. How does the firing order of an eight=cylinder motor differ 
from that of a four? 

A. In view of the fact that the usual V-type eight-cylinder 
motor is nothing more nor less than two four-cylinder motors work¬ 
ing on the same crankshaft, or, as it may be better put, with a com¬ 
mon crankshaft, the firing order is simply that of two four-cylinder 
motors in which the ignition alternates from one motor to the other. 
That is, in addition to alternating from one pair of cylinders to the 
other, as already described, the firing also must alternate from one 
group of cylinders to the other, so as to maintain the impulse balance 
of the motor. The explosion in a right-hand cylinder must always 
be followed by the firing of a left-hand cylinder. 

Q. What are the usual firing orders of eight=cylinder motors? 

A. The same as those for fours, i.e., 1-2-4-3 and 1-3-4-2, 


ELECTRICAL EQUIPMENT 


229 


alternating from one group of four cylinders to the other, as, for 
example, LI -R:LL2-R1-L4-R2-L3-R4, or Rl -L4-R3-L2-R4-Ll-R2-L:h 
The number of combinations is increased as the firing order may 
start with the first right or the first left cylinder. 

Q, How does the firing order of the twelve=cylinder motor 
differ from that of the six? 

A. It bears the same relation to the six that the eight does to 
the four. In other words, the twelve-cylinder motor is practically 
two six-cylinder motors, or two groups of six pistons each, working 
on a common crankshaft. 

Q. Give the firing orders of two of the twelve=cylinder motors 
now in use? 

A. The Packard twin-six firing order is R1-L6-R4-L3-R2-L5- 
R6-L1-R3-L4-R5-L2. That of the National twelve is R1-L6-R5- 
L2-R3-L4-R6-L1-R2-L5-R4-L3. 

Q. What is the effect of a cylinder firing out of order? 

A. The spark may either occur when there is no gas in the 
combustion chamber, in which case that cylinder will miss when it 
should fire, or it may take place in a cylinder that will be fired so 
as to act against the other cylinders instead of icith them. In either 
case, irregular running will result. Where there are either eight or 
twelve cylinders, the fact that one is either missing or firing against 
the others will not stop the operation of the motor; the misfiring of 
a single cylinder in a twelve is scarcely perceptible, except at low 
speeds. But in a four or sixj the misplacing of a pair of spark-plug 
leads will prevent the running of the motor altogether. 

Q. Is it possible to have one cylinder fire out of order? 

A. It will be evident that, as the cylinders in all automobile 
motors fire in alternate pairs, the misplacing of one spark-plug lead 
naturally involves the dislocation of its mate or its alternate. Con¬ 
sequently, one cylinder cannot fire out of order alone; two will always 
be affected. For example, in a four-cylinder motor, if the secondary 
cable to the plug of cylinder No. 1 is connected to the spark plug of 
cylinder No. 2, it is apparent that No. 2 also must be misplaced. 
Granted that there is no other fault in this respect, it will be found 
connected to the plug of No. 1. 

Q. Give a typical example of misplaced spark=plug leads 
causing improper firing order and its consequences? 


230 


ELECTRICAL EQUIPMENT 


A. Take the instance cited above. Cable No. 1 has been 
connected to cylinder No. 2; cable No. 2 has been connected to 
cylinder No. 1. The firing order is 1-2-4-3, which means that 
when the piston of cylinder No. 1 is going down on the power stroke, 
the piston of cylinder No. 2 is drawing in a fresh charge of fuel mix¬ 
ture through the open inlet valve. But, as cable No. 2 is connected 
to cylinder No. 1, no spark takes place when the piston finishes its 
upward travel on the compression stroke, and no explosion results. 
The spark instead of occurring in cylinder No. 1, takes place in 
cylinder No. 2, and may ignite the incoming gas, resulting in a weak 
explosion or a back-fire through the inlet valve. If the placing of the 
inlet valve be such that the incoming charge is not fired by 
the spark of cylinder No. 1, but takes place in cylinder No. 2, on the 
suction stroke, nothing will occur in cylinder No. 2, either. When 
its piston comes up on the compression stroke ready for firing, the 
spark occurs in cylinder No. 1, and the fresh charge passes out of the 
exhaust valve of cylinder No. 2 without being fired. In other words, 
both cylinders No. 1 and No. 2 miss. Cylinders Nos. 3 and 4 being 
connected up in the proper order, however, they will fire as they 
should, but in a four-cylinder motor they are not sufficient to keep 
the motor turning over steadily. It will give two jerky explosions 
and stop. After cranking several times, cylinder No. 2 will become 
more or less filled with fresh gas, and a back-fire will result at every 
other revolution, or every time it is the turn of cylinder No. 2 to fire. 
Cylinder No. 1 is not likely to back-fire, since the spark is occurring 
in its combustion chamber on the exhaust stroke. 

Q. What would be the effect if, instead of connecting to 
cylinder No. 1, the lead of cylinder No. 2 misconnected to No. 3? 

A. As the firing order of the motor is 1-2-4-3, it will be 
evident (the other cables being correctly connected) that cylinder 
No. 1 will fire properly; No. 2 will miss; No. 4 will fire properly; and 
No. 3 will either miss or back-fire; so that the motor as a whole will 
run very jerkily; although it will continue to run on this combina¬ 
tion, i.e., one operating cylinder in each alternate pair firing a revolu¬ 
tion apart. In this case, when the piston of cylinder No. 2 has just 
finished compressing its charge and should fire it, its spark takes 
place in the combustion chamber of cylinder No. 3, which is then 
exhausting, so that it is also much more likely to miss than to back- 


ELECTRICAL EQUIPMENT 


231 


fire. The effect will be practically the same as if no spark at all 
took place in either of these two cylinders, and the motor will run 
on one pair alone. 

Q. Is it any more difficult to locate trouble due to the cables 
being connected in the wrong firing order, in motors having six, 
eight, and twelve cylinders? 

A. The greater number of cylinders would naturally add to the 
confusion, and the fact that it is not easy to tell off-hand when one 
cylinder in an eight or twelve is missing, contributes to the difficulty 
of locating the one at fault. On the other hand, however, the spark¬ 
plug leads are so designed that it is much more difficult to connect 
them up in any but the right way, as they are cut to exactly the 
proper length and are usually numbered in addition. The contacts 
of the distributor are also identified in the same manner, so that 
the connections may be readily checked without making tests of any 
kind; it is only necessary to trace the cables from the distributor to 
the plugs. The fact that the motor will continue to run on a pair 
of cylinders, even though its leads should be misplaced, is misleading, 
as the missing, or faulty running, is likely to be ascribed to a poor 
spark plug or something of that nature rather than to the real cause. 

Q. Can the firing order of the cylinders be disarranged in any 
other way than by the misplacing of the secondary cables connect= 
ing the distributor to the spark plugs? 

A. No. Since the timer, in the case of a timer- and four-vibrator- 
coil ignition system, as on the Ford, or the distributor, as on a magneto 
or battery-ignition system, makes i'cs contacts consecutively. That 
is, on a four-cylinder timer or distributor, the contacts occur in the 
order 1-2-3-4 and, unless the leads are properly connected up, the 
sparks will occur in the cylinders in the same order. To obtain the 
firing order mentioned in a previous query for a four-cylinder motor, 
i.e., 1-2-4-3, contact No. 1 of the distributor is connected to cylinder 
No. 1, contact No. 2 to cylinder No. 2, contact No. 3 to cylinder 
No. 4, and contact No. 4 to cylinder No. 3. The connections would 
naturally be the same in the case of a timer, as there is then an 
independent induction coil for each cylinder of the motor. 

Q. Has grounding or short=circuiting of the secondary leads 
any effect on the firing order of the motor? 

A. This may be the case where two secondary cables touch 


232 


ELECTRICAL EQUIPMENT 


each other and there is a short-circuit at the point of contact. For 
example, assume that the cables of cylinders No. 1 and No. 2 cross 
each other in running from the distributor to their respective spark 
plugs (this is poor practice in wiring, but it is nothing unusual to 
see it on old cars) and that there is a leak in their insulation at this 
point. After being in service for some time, spark-plug points burn 
away unevenly, so that the gap at one is less than at the other. 
Consequently, there will be less resistance at this plug than at the 
one with the wider gap; in short, the combined resistance of the 
leakage gap where the cables cross and that of the spark plug with 
the smaller opening may be less than that of the plug which has 
burned further apart. Then the current intended to produce a 
spark at this plug will leak through the insulation and produce 
a spark at the other plug instead, and the latter will fire out of 
order while the first plug will miss. 

Q. Does a change in the firing order of a motor have any 
effect on its running? For example, assume a four=cylinder motor 
designed to run with the firing order of 1 =2=4=3. Will such a 
motor run any better if the firing order be shifted to 1 =3=4=2, or to 
2= I =3=4? Can this be done easily? 

A. So far as the actual operation of the motor is concerned, 
such a change would have no particular effect, as a cylinder of each 
alternate pair would fire consecutively. The change can be made 
without any difficulty, on the average motor, by providing new 
secondary cables, as the latter are usually cut to about the right 
length to reach from the distributor to the spark plugs in the firing 
order for which the motor is originally designed. The distributor 
would then have to be connected to the plugs in the following way: 
distributor contact No. 1 to cylinder No. 2, contact No. 2 to cylin¬ 
der No. 1, contact No. 3 to cylinder No. 3, and contact No. 4 to 
cylinder No. 4. 

Q. Why do different manufacturers adopt different firing 
orders, if there is no particular benefit to be derived from one as 
compared with another? 

A. Chiefly to adapt the wiring more conveniently to the loca¬ 
tion of other essentials, such as the magneto or the distributor of a 
battery system, although the intake manifold design may influence 
the choice. 


ELECTRICAL EQUIPMENT 283 

SPARK PLUGS 

Q. What are the usual causes of failure of the spark plug? 

A. An accumulation of carbon on the inner end of the porcelain 
and the shell, causing a short-circuit; broken porcelain; points 
burned too far apart to permit spark to pass. 

Q. When there is a hissing noise at the plug, or when oil 
squirted on it bubbles violently with the motor running, what does 
it indicate? 

A. Either that the porcelain of the plug is not screwed down 
tightly on its gasket on the shell, the porcelain is broken, or the plug 
itself is not tight in the cylinder. 

Q. What is the cause of a discharge across the porcelain of the 
plug? 

A. The points are too far apart, or the porcelain is broken; 
usually the former. This usually will be noted only on plugs having 
very short porcelains as where the latter are long, the distance is 
much greater than the maximum to which the points can be sep¬ 
arated and any spark that would occur owing to the latter cause 
would take place at the safety gap. 

Q. Why is it that when a good spark will occur between the 
points of a plug in the open air, an equally good spark cannot be 
obtained in the cylinder with the same distance between the points 
of the plug? 

A. Compressing air increases its resistance to the electric 
current, so that a stronger current is necessary to produce the same 
spark under compression in the cylinder, as may be obtained in the 
open air with less current. This is one of the-symptoms of a weak 
starting battery (dry cells). All the plugs will spark satisfactorily 
when removed from the cylinders, but it is found very difficult to 
start the engine by cranking. When fresh cells cannot be had, it 
may be overcome temporarily by adjusting the points of the plugs 
closer together, in this way obtaining a satisfactory spark with less 
current. 

Q. What is the proper distance between the points of the 
spark plugs? 

A. For good working with a magneto, this should not exceed 
A inch. With storage-battery ignition, it may be greater, but it is 
good practice to employ the smaller gap with either. 


234 


ELECTRICAL EQUIPMENT 


Q. How rapidly do the electrodes of the spark plugs burn 
away, and what effect does this have? 

A. This will depend upon the plugs themselves and the character 
of the current supply. The cheaper plugs with ordinary iron-wire 
electrodes will burn away very rapidly, becoming much too widely 
separated in a few weeks’ use. With better grade plugs, using a hard 
alloy for the electrodes, the time will depend more or less on the 
magneto, or where a storage battery is employed, on the coil. Some 
produce a very much hotter spark than others and, consequently, 
burn the plugs away that much sooner; but a good plug ought not 
to need adjustment under two or three months of ordinary running. 
The fact that the plug points have burned too far apart will be 
evidenced by a very perceptible falling off in the power; by missing 
spasmodically in different cylinders at low speeds; and by an occa¬ 
sional discharge across the porcelain on the outside of the plug, if 
the latter is of the short type. 

Q. What can be done when there is an escape of compression 
around the porcelain of the plug? 

A. If the porcelain is not broken, this can be remedied by 
turning down the gland or packing nut which holds the porcelain in 
the metal shell. There is an asbestos washer under this packing 
nut, and tightening the latter causes it to fill completely any space 
between the porcelain and the shell. The nut should be given only 
a fraction of a turn, and the tightening should be done when the 
plug is cold; if it is tightened when very hot, the contraction due to 
the cold is liable to crack the porcelain. 

Q. What is one of the commonest ways of breaking spark= 
plug porcelains? 

A. The use of a big wrench in putting the plugs into the 
cylinders. Only a spark-plug wrench or a small wrench having but 
a 3-inch or a 4-inch handle should be employed. The leverage 
available with the big wrench is so great that the porcelain is crushed, 
frequently without the knowledge of the man using it. 

Q. How can a broken porcelain be detected? 

A. Usually by grasping the plug between the fingers and try¬ 
ing to turn the porcelain sideways or to revolve it. Any play is 
generally an indication that the porcelain is broken, though some¬ 
times they will loosen up so much under the influence of vibration 


ELECTRICAL EQUIPMENT 


235 


tliat they may be turned easily with the fingers. Tightening the 
packing nut will overcome this. Where this treatment does not 
locate a break, squirting a little oil on the porcelain while the motor 
is running will do so. 

Q. How long should a good plug stay in service? 

A. This is hard to average, but with occasional adjustment of 
the points, a good plug will frequently continue to give satisfactory 
service for several thousand miles; some have been known to run for 
well over 10,000 miles, and still continue to operate satisfactorily. 
When the motor does not run properly and the plugs are suspected, 
it is better to try the effect of a new set and note the running of the 
motor carefully, before discarding the old ones, as the fault will 
frequently be found elsewhere. The first thing that many repair 
men do with a motor that is a bit off is to throw away a perfectly 
good set of spark plugs. 

Q. What is a “series”=type plug, and what advantages has it? 

A. This is a type of plug fitted with two insulated terminals, 
instead of one, as in the ordinary type, as it does not make a ground 
connection on the motor by being screwed into the cylinder. It is 
intended to be used in series with an ordinary plug, hence the name. 
The current passes through the series plug first, and then, through 
the second plug of the ordinary type, to the ground, thus producing 
two sparks instead of one. The advantages claimed for its use are a 
more rapid and thorough combustion of the mixture, due to the spark 
occuring at two widely separated places in the combustion chamber; 
but, in actual practice, the gain is not sufficient to warrant the extra 
complication, so that this type of plug is seldom used. 

Q. What is the object of fitting a plug with several sparking 
terminals, or electrodes? 

A. The current will always follow the path of least resistance 
and will accordingly bridge the smallest gap. The sparking will 
start at this gap and, when that particular electrode burns away, 
will shift to one of the others until that has also burned too far open, 
i.e., until its resistance becomes greater than that of the next one, 
and so on. Such a plug should stay in service longer without the 
necessity of adjusting the gap, but, apart from this, it has no par¬ 
ticular advantage, as the short-circuiting of one of the gaps renders 
all of them useless. 


23G 


ELECTRICAL EQUIPMENT 


Q. What threads are generally used on spark plugs, and which 
thread is to be preferred, from the repair man's point of view? 

A. Llalf-inch iron pipe, metric and S.A.E. standard. Plugs 
with iron-pipe threads are employed only on the cheaper cars; metric- 
threaded plugs will be found on foreign cars only, and S.A.E. standard 
plugs (I inch-18) on most, if not all, of the better American cars 
dating from about 1913 on. All work equally well so far as holding 
compression is concerned. The iron-pipe plug is likely to cause trouble 
in this way sooner than the others, as they do not depend upon the 
thread itself to prevent leakage. The S.A.E. standard plug is 
preferable, being a better mechanical product than the iron-pipe 
plug as the threads of the latter are not so accurate, and the plug 
itself is usually not so well made. 

Q. When a spark plug leaks at the base, i.e., at the point 
where it is screwed into the cylinder, what is the cause? 

A. If of the iron-pipe type which depends entirely upon its 
tapered thread to hold the compression, a section of the thread may 
have been damaged in handling. With either of the other types, the 
plug may not be seated snugly enough on its gasket, in which case 
a quarter-turn in will usually remedy the leak. If it does not, the 
gasket should be replaced with a new one. 

Q. Is there any danger of turning an iron=pipe plug in too 
tightly? 

A. If screwed home too tightly while the motor is hot, the plug 
may bind and become very difficult to remove, sometimes necessi¬ 
tating drilling it out and re-tapping the hole. 

Q. Is the priming type of plug of any particular advantage? 

A. On low-priced cars not fitted with pet cocks in the cylinders, 
it is an aid to starting in cold weather; though, as a matter of fact, 
the priming inlet of the plug is likely to become clogged with soot, 
so that it cannot be used for injecting gasoline into the cylinders. 

Q. Why has the magnetic type of spark plug not come into 
general use? 

A. It is an expensive type of plug to make and is more subject to 
derangement than the ordinary kind. It is only intended to be used 
with a low-tension magneto and plain-spark coil (single winding on an 
iron core), and this type of magneto has long since become obsolete 
on the automobile. 


ELECTRICAL EQUIPMENT 


237 


Q. Is porcelain or mica preferable, as the insulator of the plug? 

A. While mica is practically unbreakable, it is liable to become 
saturated with oil and dirt, causing leaks that are hard to trace; 
so that the use of porcelain is preferable, despite its liability to 
breakage. 

Q. Is changing from one make of plug to another likely to cause 
any difference in the running of a motor? 

A. As the power of the motor is dependent, to a very large 
extent, upon the proper ignition of the charge, a change from one 
make of plug to another will sometimes make a very marked differ¬ 
ence. Because of the great amount of variation in the width of the 
cooling jacket and the thickness of the cylinder walls, certain types 
of plugs are particularly adapted to certain makes of motors. In 
fact, the plugs have been designed especially for service on those 
motors. For example, some motors require an unusually long plug 
to permit of the sparking points extending well into the combustion 
chamber. In others, a plug of this type might interfere with the 
piston when at upper dead center. Always use the type of plug 
recommended by the manufacturer of the car. 

Q. What is the cause of the spark plugs in a motor becoming 
fouled very rapidly? 

A. An excess of lubricating oil is finding its way into the com¬ 
bustion chamber, and its burning there deposits a heavy layer of 
carbon on the ends of the plugs. This may be due to leaky piston 
rings; the use of improper oil for the motor, as where a very light oil, 
instead of a heavy bodied lubricant is used in a motor intended for 
the latter; or, in old cars, the lack of baffle plates between the crank¬ 
case and cylinders. Running the motor with an over-rich fuel mix¬ 
ture will also cause sooting of the plugs. The use of a heavier oil 
and with it a certain proportion of flake graphite, or “Gredag”, will 
often greatly improve the compression of an old motor and effectively 
remedy this trouble. 

Q. Is it advisable to use lubricating oil mixed with graphite 
in all old cars? 

A. It is usually good practice, except on the Ford, as the mag¬ 
neto of the latter runs in oil splashed back from the crankcase, and 
the presence of graphite in this oil would short-circuit the magneto. 
In case this has been done on a Ford, it would be necessary to wash 


238 


ELECTRICAL EQUIPMENT 


the magneto out very tliorouglily with gasoline to remove all traces 
of the graphite, and even that might not remedy the short-circuiting. 

Q. When the plug in only one cylinder of a motor continually 
soots up very rapidly, what is the cause? 

A. That particular cylinder is being flooded with oil, and an 
excess amount of it is reaching the combustion chamber. A piston 
ring may have broken in that cylinder, the rings may have worked 
around until their openings are in line with one another, or the supply 
system may have become deranged, causing an excess of oil to reach 
the section of the crankcase directly under that cylinder. 

Q. Is there any way of knowing to a certainty before undertak= 
ing an inspection, whether missing is due to a faulty plug or to some 
derangement of the carburetor? 

A. If the miss continually occurs in the same cylinder, it may 
be put down as due to the plug or wiring of that particular cylinder, 
even though the plug, when tested from the outside (i.e., without 
removing it from the cylinder), is apparently working properly. 
When the missing is spasmodic, occurring first at one cylinder and then 
at another, it is more likely to be due to faulty carburetor adjustment 
or a partially clogged carburetor nozzle. A weak dry battery, 
however, will produce similar symptoms; failing fuel supply also will, 
though, in this case, the whole motor will run jerkily one moment, 
speed up the next, and then almost stop, only to repeat the per¬ 
formance. 

Q. Is the usual test, made by unclipping the secondary cable 
from the plug and holding it near the terminal with the motor run= 
ning, always conclusive as to the proper working of the plug, when a 
spark occurs between the two? 

A. No. Since a short-circuited plug will not prevent a spark from 
passing between its outer terminal and the end of the cable held near 
it. The gap made by disconnecting the secondary cable and holding 
it a short distance away has simply taken the place of the gap which 
should exist between the plug points. This test is conclusive only 
as to the proper functioning of the distributor and the integrity of 
the wiring connecting that particular plug. 

Q. When the motor misses spasmodically, and there are inter= 
mittent discharges of high=tension current at different points on the 
cylinders, while it is running,'what is the cause? 


ELECTRICAL EQUIPMENT 


239 


A. Moisture. The secondary cables have become wet enough 
to cause leakage of the high-tension current; usually the result of the 
careless use of the hose in washing. The only remedy is to run the 
motor continuously until the heat dries things out thoroughly. 

Q. When no spark plug is obtainable at any of the plugs, so that 
the motor cannot be started, in what order should the cause of the 
trouble be run down? 

A. If a dry battery is used as the source of current, first see 
that it is not exhausted by testing with a small ammeter. Each cell 
should show 10 amperes or more. If one is considerably below the 
others, it reduces them to its level. Where a storage battery is used, 
switch on the lights as a test. They should burn brightly. Provided 
there is no failure of the current, inspect the interrupter, or contact 
breaker; see that its points separate when the high part of the cam 
strikes the arm carrying the movable point. If they do not separate, 
no current is induced in the secondary winding, and an adjustment of 
the points, to open about the space represented by an ordinary 
visiting card, will remedy the trouble. If the points open properly, 
inspect the wiring and connections between the interrupter and the 
battery. Should both the interrupter and its wiring be O. K., note 
whether the ground connection from the coil is fast. Failing all of 
these, inspect the high-tension distributor. This is about the order 
in which the trouble would be likely to occur. 

Q. When the motor continues to run after the current has 
been turned off, what is the cause? 

A. The cylinders have become so hot, due either to lack of oil or 
or low water in the cooling system, failure of circulation, etc., that 
either the spark-plug electrodes have become red hot, or particles 
of carbon, deposited in the combustion chamber, have become incan¬ 
descent, thus firing the charge. The fuel supply must be shut off 
and the motor allowed to cool. 

Q. Should the motor back=fire when attempting to start, even 
though the spark=advance lever has been pulled back as far as it will 
go, what is causing the trouble? 

A. The linkage connecting the spark-advance lever with the 
breaker box of the magneto or of the interrupter (battery system) has 
parted at some point, so that it no longer moves the breaker box to 
retard the time of ignition. 


240 


ELECTRICAL EQUIPMENT 


REGULATION DEVICES 
Interrupters and Timers 

Q. How does an interrupter operate? 

A. It is normally closed, short-circuiting the battery on the 
primary winding of the coil until just before it is necessary for the 
spark to occur in the cylinder; a cam then separates the contact 
points, and the high-tension current induced in the secondary wind¬ 
ing of the coil jumps the gap of the plug. In the case of a magneto, 
the winding of the armature is short-circuited on itself to permit it 
to “build up”, so that when the interrupter contacts are opened by 
the cam, the peak or highest value of the current wave generated 
is utilized. The opening of the circuit in either case occurs at the 
same time the distributor arm is passing one of its contacts. 

Q. How does a timer operate? 

A. Contacts, insulated from each other, their number corre¬ 
sponding to the number of cylinders, are located at equidistant points 
on the inner circumference of the timer housing, while the shaft carries 
a single contact which in its revolution successively touches each one 
of the stationary contacts. Where separate vibrator coils are used, as 
on the Ford, each stationary contact corresponds to one of the coils. 

Q. Do interrupters and timers fail from the same causes, and 
what are they? 

A. No. The cause of failure in one case is the reverse of that in 
the other. An interrupter fails when it does not open the circuit, 
and a timer when it does not close it. Dirt and wear are the usual 
causes of failure in both cases; moisture is also responsible at times. 
Test by having an assistant turn the engine over slowly by hand 
and watch the operation of the interrupter; if the cam fails to sep¬ 
arate the contact points, true up their faces with fine sandpaper and 
test again. (This does not apply to Atwater Kent interrupters. 
See description.) Stop with the cam in the opening position and 
see if a sheet of ordinary paper can be slipped between the contacts. 
See that there is not an excess of oil in the housing, as oil on the con¬ 
tact point insulates them. In the case of a timer, see that the spring 
of the movable contact has sufficient tension to keep it pressed firmly 
against the stationary contacts as it revolves; note whether sufficient 
wear has occurred to cause poor contact even with sufficient spring 
})ressure. 


ELECTRICAL EQUIPMENT 


241 


Q. How far should the contacts of an interrupter separate? 

A. This differs somewhat with different systems, but in the 
case of the interrupters used on battery systems, it is very small, 
seldom exceeding a few thousandths of an inch. In the case of the 
Atwater Kent interrupter, this is .010 to .012 inch. (Coated cata¬ 
logue paper is .005 to .007 inch thick; a thin visiting card is .010 to 
.015 inch thick.) 

Q. How does the Atwater Kent interrupter differ from other 
battery interrupters? 

A. The circuit is normally open and only remains closed 
momentarily before being opened by the dropping of the lifter into 
its notch on the shaft. 

Q. Can this interrupter be tested in the same way as that just 
described? 

A. No. The movement of the lifter in striking the latch to close 
the circuit is so rapid that it cannot be detected with the unaided 
eye, even though the engine be turned over very slowly by hand. 

Q. What will cause this interrupter to fail? 

A. Wear of the lifter to an extent where it will not engage the 
notches of the shaft properly, usually caused by lack of oil. Other 
causes of failure are the same as for other types, generally worn or 
burned contact points. 

Q. When the contact points of an interrupter of any type 
burn away very rapidly, what is the cause? 

A. The condenser has broken down so that it is no longer pro¬ 
tecting the points from the full heating effect of the arc formed 
at the time of breaking the circuit. Use the testing-lamp outfit 
described in connection with lighting and starting systems. Apply 
one point to each of the condenser terminals; if the lamp lights, the 
condenser is short-circuited. The only practical remedy is replace¬ 
ment by the manufacturer, as even the best equipped garage is 
seldom fitted to take care of such work. 

Q. Does discoloration always indicate burned contact points, 
and how often should these points require cleaning and adjustment? 

A. No. According to the particular alloy used in the contacts 
they will assume a bright purple, an orange, or a gray tinge. The 
squareness of their surfaces and the contact they make when together 
are the best indications of whether attention is needed; if pitted or 


242 


ELECTRICAL EQUIPMENT 


high on one side, truing up will be necessary. Unless the con¬ 
denser has failed, they should not require attention oftener than 
once a season, or say 6000 to 8000 thousand miles’ running. 

Distributors 

Q. What is the function of the distributor and how does it 
differ from that of the interrupter and timer? 

A. At the same moment that the interrupter opens the primary 
circuit of the coil, or the timer makes it in the case of a vibrating coil, 
the distributor makes contact with a stationary segment representing 
a spark-plug terminal. The distributor accordingly is said to run 
synchronously with the interrupter or timer. It is practically a dupli¬ 
cate of the timer designed to handle a high-tension current, in that it 
has one revolving contact and a stationary contact for each cylinder. 

Q. Does the moving member of a distributor actually make 
contact with the stationary contacts, as in the timer? 

A. No. This is not necessary owing to the high voltage of 
the current. The moving member passes very close to the face of 
the stationary contact but does not actually touch it, thus avoiding 
wear. This applies, however, only to those early-type magnetos or 
to separate distributors employing a metal moving contact. Where 
carbon brushes are employed, they are pressed against a fiber disc 
with a metal segment countersunk flush with its face and this seg¬ 
ment passes under each carbon brush in rotation. 

Q. What are the usual causes of failure in a distributor? 

A. Short-circuits, due to moisture, dirt, or carbon dust. Owing 
to the high voltage of the current it will leak across barely perceptible 
paths caused by dampness or carbon dust. 

Q. What is the so=called ignition unit of the modern battery 
system? 

A. This is a combined contact breaker and distributor 
similar to the contact breaker and distributor of a magneto— 
in other words, a magneto minus the current-generating end. It is 
mounted on a vertical shaft and is driven through bevel, or helical 
gearing, from either the camshaft or one of the auxiliary shafts of the 
engine (i.e., water pump or magneto-drive shaft). The contact 
breaker is placed directly below the distributor, the secondary cables 
coming out of the upper face of the latter. (See description of 
Westinghouse and Connecticut units.) 


ELECTRICAL EQUIPMENT 


243 


Q. What is the “unisparker’7 

A. This is the Atwater Kent ignition unit and is similar in gen¬ 
eral design to those referred to above but it is an ‘‘open-circuit” type, 
while they are “closed-circuit”. The term is a trade name derived 
from the fact that the contact breaker makes but a single spark, as 
compared with the vibrator coil which produces a series of sparks 
only one of which, however, is available for ignition. All contact 
breakers on magnetos and, as now used, on modern battery systems, 
produce but a single spark. The time of ignition is so limited on a 
high-speed engine, that, if this single spark fails to ignite the charge in 
the cylinder, subsequent sparks are of little value, as the piston is 
already well down on the firing stroke by the time a later spark occurs, 
and much of the force of the explosion is lost. 

Q. How is the time of ignition advanced and retarded on the 
ignition unit? 

A. Usually by altering the relation of the moving contact of the 
distributor to the stationary contacts. The distributor plate, i.e., 
the insulating disc carrying the stationary contacts is connected to 
the spark-advance lever on the steering column, and it may be moved 
part of a revolution backward or forward to advance or retard the 
time of ignition. To alter the timing, the position of the moving 
contact on its driving shaft may be shifted. For example, in the 
Delco distributor a central screw in this member is loosened, and 
the contact may then be moved in either direction with relation 
to the shaft. 

Switches 

Q. What is a “reversing’’ switch and why is it employed on 
ignition systems? 

A. It is a double-contact switch which reverses the polarity 
of the current, i.e., its direction, through the contacts of the inter¬ 
rupter every time the switch is closed. This' is done to prevent 
the burning away of the contact points in one direction which would 
cause a peak to form on the positive and a crater, or depression, on 
the negative. Reversing the direction of the current causes the 
points to become alternately negative and positive in accordance 
with the position of the switch. 

Q. What is the nature of the trouble ordinarily to be looked 
for in a switch? 


244 


ELECTUICAL EQUIPMENT 


A. Poor contact due to wear or weakening of the spring; 
broken or frayed connections causing a ground or short-circuit. 

Q. What is an automatic switch? 

A. This term is frequently applied to the battery cut-out of the 
lighting and starting system. On the Connecticut ignition system, it 
is a thermally operated switch, designed to open the circuit when the 
switch has inadvertently been left on after the engine has stopped. 

Q. Are there any troubles peculiar to automatic type of switch? 

A. None that is not equally so of any similar device such as 
the battery cut-out or the circuit breaker. 

Coils 


Q. How many different types of coils are employed in connec= 
tion with ignition systems? 

A. Three. The first and simplest of these is usually termed a 
spark coil, and consists of a single winding of coarse wire on a heavy 
iron wire core. It acts by self-induction, the circuit remaining closed 
long enough to permit the core to become thoroughly magnetized; 
the energy thus stored in the core being released when the circuit is 
broken again. This gives increased voltage at the spark plug and 
causes an “arc” rather than a spark at the latter when the terminals 
of the plug are separated. This type of coil is only employed in con¬ 
nection with low-tension or mechanically operated spark plugs, 
and this system is now used on stationary engines and motor boats 
exclusively, having long since become obsolete on the auotomobile. 

The other two types are known as induction coils, and differ 
merely in one being fitted with a vibrator while the other does not 
require this attachment to operate it. The induction coil is a minia¬ 
ture stei)-up transformer. It consists of a core of iron wires on which 
tlie primary of two or three layers of No. 16 or No. 18 wire is wound 
almost the full length of the core, and a secondary of many thousand 
turns of very fine wire, such as No. 36 or 38 B. & S. gage, or even No.40, 
which is almost as fine as a hair. In coils of the best construction, 
this fine wire is wound in pancakes, or narrow sections, several of 
which are necessary to complete the secondary. Their terminals are 
connected in series thus making practically a single winding. Heavy 
insulation is placed between the primary and secondary windings, 
and the containing case is usually filled with an insulating compound, 
melted into it and becoming solid when cold. 


ET.ECTT^TCAL EQUIPMENT 


245 

Q. Why is an induction coil termed a “step=up” transformer? 

A. It literally steps up or raises the voltage of the current sent 
through it. The primary winding is connected to the source of cur¬ 
rent and the secondary to the spark plugs through the distributor. 

Q. Is the action of the coil based on the same principle as that 
utilized in generators and motors? 

A. The principle of induction, as explained in Part I, is 
the same in all three, though it is utilized in a different manner in 
the induction coil. Instead of a moving coil of wire cutting the lines 
of force of a magnet, impulses are produced either by sending a pul¬ 
sating current through the primary winding or by using an alternating 
current. 

Q. How is this pulsating current produced in the primary? 

A. By placing a vibrator in series with the primary winding. 

Q. Of what does the vibrator consist, and how does it act? 

A. It consists of a spring-hinged armature and a pair of adjust¬ 
able contact points, exactly as in an ordinary electric bell or buzzer. 
This armature is located directly over the end of the core of the coil 
and close to it. When a current passes through the primary winding, 
it makes the core strongly magnetic and attracts the armature. This 
pulls the latter away from the stationary contact point and breaks 
the circuit, so that the core is no longer magnetic. The spring 
immediately pulls the armature back and recloses the circuit, this 
action taking place at high speed as long as the current is on. 

Q. Why is the vibrator not necessary when an alternating 
current is used? 

A. The rise and fall of the current wave, from zero to maximum 
and back again in the reverse direction, produces the same effect of 
magnetizing and demagnetizing the core of the coil very rapidly. 

Q. Is the vibrator coil as rapid in action as the induction coil 
used with alternating current? 

A. No. Since there is a mechanical as well as an electric ‘‘lag”, 
or delay. The inertia of the armature must be overcome before it can 
be pulled down by the core, and to do this on a vibrator adjusted to 
withstand road shocks, the core must become saturated, or strongly 
magnetic. The time necessary to overcome the inertia of the arma¬ 
ture is the mechanical lag, while that required for the core to become 
saturated is the electrical lag. In combination they make the 


240 


ELECTRICAL EQUIPMENT 


vibrator coil very much slower in action than the other type, and 
this is greatly accentuated by a stiff adjustment of the vibrator 
spring. 

Q. Why is a vibrator necessary with one type of battery ignition 
and not with another, i.e., the so=called modern battery ignition? 

A. Owing to the type of timer or interrupter, frequently erro¬ 
neously termed the “commutator”, employed on the two systems. 

Q. What is the difference between the old=style timer and the 
modern interrupter? 

A. In the former, a long contact is provided for each cylinder 
and the revolving contact member is in touch with this for quite an 
appreciable period of time, during all of which the vibrator of a coil 
of that type is in action. If the contact member of the timer were 
depended upon to make and break the circuit through the coil to 
obtain the spark in the cylinder, the stationary contacts in the housing 
would have to be very much shorter, and no provision for advancing 
and retarding the time of ignition would be available. Furthermore, 
the wiping contact of the ordinary style of timer is not adaptable to 
the extremely rapid make-and-break that is necessary for this purpose. 
The interrupter of the modern battery system is designed along 
practically the same lines as the contact breaker used in the primary 
circuit of a high-tension magneto or the only circuit used on a low- 
tension magneto. Its parts are made very small and light and with 
great accuracy, so that its inertia is reduced to the minimum and it 
will act with extreme rapidity. The gap is so small and the rapidity 
of action so great that the movement is often not visible to the unaided 
eye. It is practically a mechanical vibrator designed to give a single 
make-and-break at exactly the right moment as compared with the 
electrical vibrator, which must be started well in advance of the 
moment ignition is required, and which continues in action after the 
spark has occurred in the cylinder. Consequently, both the mechan¬ 
ical and the electrical lag, which make the vibrator coil comparatively 
slow in action, are reduced to a minimum, and the amount of current 
necessary is cut to a fraction of that required by the latter. 

Q. How can the speed of operation of a vibrator be judged? 

A. By the note it produces in action. A low note well down 
the scale denotes slow action; the higher the note, or buzzing, the more 
rapid the vibrator is acting. 


ELECTRICAL EQUIPMENT 247 

Q. What effect on the ignition has the speed with which the 
vibrator operates? 

A. A slow-moving vibrator increases the amount of lag and 
retards the ignition accordingly. This causes a corresponding 
reduction in the power of the engine, as the spark does not occur at the 
proper time to give the best efficiency. 

Q. What is a master vibrator? 

A. The vibrator type of coil on a multi-cylinder engine requires 
an individual coil for each cylinder, and it is often found difficult to 
adjust all of the vibrators so that they will act uniformly. If some are 
stiffer than others they will not act so rapidly, and the time of explo¬ 
sion in the cylinders they control will be delayed, causing uneven 
running of the engine. To overcome this, an extra coil with a spe¬ 
cially made vibrator is connected in series with the timer and the other 
coils, so that its vibrators acts for each coil in turn, the vibrators of 
the other coils either being removed or screwed down hard so that 
they cannot act. This makes but one vibrator to adjust, instead of 
the four on a four-cylinder engine. As it controls all of the other coils, 
it is known as a master vibrator. 

Q. Is the vibrator type of coil still in general use? 

A. It has long since become obsolete on all cars except the Ford. 

Q. As the Ford magneto produces an alternating current, why 
are vibrator coils necessary? 

A. The Ford magneto has sixteen poles, and the armature which 
serves as the flywheel, carries sixteen coils, so that the number of 
alternations at the high speed at which the Ford motor runs, is very 
great. These alternations, or cycles, are so rapid that they overlap 
each other, as is evidenced by the steady burning of the incandescent 
headlights. The induction coil does not act quickly enough to be 
affected by the change of polarity so that a vibrator is necessary on 
each coil to produce a sufficiently hot spark for ignition. 

Q. How can the four vibrators of the Ford coil be adjusted so as 
to operate uniformly? 

A. The fact that they are not doing so, will be evidenced by 
the uneven running of the motor. Determine, by holding down the 
vibrators, one after the other, which cylinder or cylinders are lagging 
behind the others in firing. This will cut out the cylinders in turn; 
in fact, two may be held down at once, and the action of the remaining 


248 


ELECTRICAL EQUIPMENT 


pair noted. When the cylinder, or cylinders, at fault have been 
determined, adjust one at a time by releasing the lock nut of the 
adjusting screw of the vibrator and turning it up or down, according 
to whether improvement in running is noted, or not. Usually only a 
small fraction of a turn one way or the other will be necessary. Turn 
the screw very slowly and very little at a time and, when the proper 
adjustment of the screw has been secured, lock in place again securely. 
Ordinarily, the proper adjustment may be secured simply by noting 
the running of the motor. When all the cylinders fire regularly and 
without any apparent lag, the adjustment is considered correct. To 
secure a finer adjustment, a small portable ammeter, reading by 
tenths to three or five amperes, may be used. Connect this in series 
with each one of the coils in turn, and note the reading at which the 
coil acts most rapidly. The other vibrators may then be adjusted to 
give the same reading. When dry batteries were relied upon for 
ignition, this test was employed to reduce the current consumption 
to the minimum but with the excess supply of current from the Ford 
magneto, this is not necessary, and the vibrators may be adjusted to 
the reading giving the most rapid action, regardless of the current 
consumption. This test may be employed also to check the operation 
of the magneto, as its current output may have fallen off to a point 
where it is no longer sufficient to operate the coils satisfactorily. 

Q. Why is a vibrator not necessary on the alternating current 
generated by the ordinary type of magneto? 

A. The latter has but two field poles and a single coil on a two- 
pole armature, so that its cycles are very much fewer in number, and 
there is definite drop in the current, from the maximum to an absolute 
zero, twice in every revolution. Assuming a speed of 1200 r.p.m., the 
ordinary magneto would be running 600 r.p.m., as it is driven by a 
half-time shaft of the motor. This is 10 revolutions per second times 
2 cycles per revolution which gives an alternating current of but 20 
cycles, or one which would cause an incandescent lamp to flicker very 
badly. The Ford magneto, on the other hand, is directly on the 
crankshaft. Consequently, it is turning 20 revolutions per second, 
and its coils produce 16 cycles per revolution, or 320 cycles per second, 
equivalent to 19,200 alternations per minute. For ordinary commer¬ 
cial lighting, only 60 cycles per second are necessary to produce a 
steady light. The drop to zero in the current curve of the ordinary 


ELECTRICAL EQUIPMENT 


249 


magneto permits the core of the coil to become demagnetized, and it 
is then remagnetized by the subsequent rise to the maximum value 
in the other direction, so that no vibrator is necessary to accomplish 
this alternate magnetizing and demagnetizing of the core which is 
needed to produce the inductive elfect in the coil or transformer. 

Q. How many connections are there on a coil? 


A. Three; one to the primary, from the battery or magneto; 
one from the secondary, to the distributor, in the case of a single coil, 
or to the spark plug in the case of a multiple coil; and one to the 
ground. The last named is referred to as a common-ground connec¬ 
tion, as it grounds one side of both the primary and secondary wind¬ 
ings of the coil. 

Q. How are these connections made? 

A. On the single non-vibrator coil, as used with an ordinary 
magneto, by means of wire cables from the magneto to the primary 
of the coil, from the secondary of the latter to the high-tension dis¬ 
tributor. In the case of the Ford multiple-vibrator coils, each coil 
is an independent unit, having brass strap connections attached to the 
bottom of the coil-unit case. These straps are of spring brass and 
they bear against corresponding plates of brass in the bottom of the 
coU box fastened to the dash. Simply lifting the coil unit out of 
the box breaks the connection and automatically remakes it when the 
coil is replaced. Due to this type of connection, irregular firing of 
the Ford motor will frequently be found to result from the cover of 
the coil box not being snapped down tightly. This permits the coil 
units to jump around in the box owing to the jolting and vibration, 
and every time they are jolted up off their connections, a cylinder 
fails to fire, as the coil does not receive any current. Coils used in 
connection with modern battery systems are often grounded in the 
same manner as the magneto, i.e., by their attachment to a plate on 
the motor the ground wires of the coil being connected to this plate. 

Q. When a coil fails to operate, how can it be tested for faults? 

A. In the case of the single coil, used in connection with an ordi¬ 
nary magneto, disconnect it and test with the testing-lamp outfit 
described in connection with lighting and starting systems. Place 
one of the terminals of the testing set on the common-ground connec¬ 
tion, then place the other in turn on the primary and the secondary 
leads. If the windings are intact, the lamp should light each time. 


250 


ELECTRICAL EQUIPMENT 


Should it fail to do so, the covers of the coil may be removed to note 
if a wire has broken just beneath it. This is most likely to be the case 
with the secondary, owin^ to the very fine wire used. If there is 
no break, either at this point or where the primary lead is connected 
to its winding, it will be necessary to return the coil to the manufac¬ 
turer as there is an internal short-circuit, which cannot be repaired in 
the garage. The only difference between the method above outlined 
for a single coil and that of a unit-vibrator coil as used on the Ford, 
is to touch the test points to the brass strap connections representing 
the different windings. 

Q. Why is but one coil used in connection with an ordinary 
magneto, while four are employed on the Ford? 

A. Where a single coil is used, the secondary current is led to a 
distributor from which it is again led to the various spark plugs in the 
proper order of firing. No distributor is employed on the Ford, so 
that a vibrator coil is necessary for each cylinder. The connections 
from the coils to the plugs are made in the same order as they would 
be to a distributor. 

Q. When a vibrator coil cannot be made to function properly 
by adjusting the contact screw, what should be done? 

A. The contacts should be trued up with a very fine file, as 
failure to function will usually be caused by their having become badly 
burned away or pitted, thus making poor electrical contact. Where 
the above is the case and the contact points are square and true, 
it is only necessary to clean them by drawing a worn piece of fine 
sandpaper between them several times, first on one side and then on the 
other. See that none of the holding screws of the vibrator frame have 
become loosened, and that the lock nut of the movable contact holds 
the latter firmly in place when tightened up. 

IGNITION BATTERIES 

Q. What types of batteries or cells are used for ignition? 

A. Dry cells and storage cells, or accumulators. (For queries 
on the latter see under ‘‘Battery” in Lighting and Starting Section.) 

Q. What type of cell is the so=called dry cell? 

A. It is a primary cell, i.e., one in which a current of electricity 
is generated by chemical reaction, and is technically known as an 
“open-circuit” battery. 


ELECTRICAL EQUIPMENT 251 


Q. Of what does the dry cell consist, and how much current 
does it generate? 


A. The elements are the zinc container and a carbon plate cen¬ 


trally i)laee(l in the container and insulated from it at the bottom. 
Around this carbon plate, which constitutes the negative element 
(the negative element in a primary battery carries the positive termi¬ 
nal and vice versa), is packed a depolarizing agent, usually dioxide of 
manganese. The active solution is sal ammoniac in water which is 
poured in after the cell is assembled and filled with the depolarizer, 
and then the cell is sealed at the top with pitch, so that it is dry in 
name only. No chemical action can take place without the presence 
of moisture. 

A dry cell of the ignition type generates a current of 20 to 25 
amperes (when new) at a potential of 1| volts. 

i 

Q. Why is a depolarizing agent necessary? 

A. The action of the cell generates hydrogen gas, which quickly 
covers the carbon plate in the form of globules, rendering it inactive. 
The cell is then said to be polarized, and the current generated drops 
off very rapidly. This may be illustrated by placing an ammeter 
across the terminals of a new cell. The ammeter reading will remain 
at 20 amperes for a short time and then will quickly drop until, at the 
end of five minutes, the instrument will show scarcely any reading at 
all. If the connection is broken and the cell allowed to stand for ten 
minutes, it will again show almost as high a reading as before; at the 
end of an hour or more of rest, it will give practically the same reading. 
The depolarizing agent has in the meantime absorbed the gas which 
prevented the action of the cell. 

Q. Why is it termed an open=circuit cell? 

A. Because it will only produce its normal output for very short 
periods and must be allowed to rest between each demand for current. 
Otherwise, it will quickly become polarized and, if tested in this con¬ 
dition, will apparently be dead. It cannot be used where a steady 
current is required but must normally stand on open circuit. 

Q. How is the dry cell employed for ignition? 

A. Four cells are connected in series to give current at 6 volts, 
and a battery of this type is ordinarily employed, either as an emer¬ 
gency stand-by or simply for starting purposes. Where an open- 
circuit type of interrupter is employed, such as the Atwater Kent, it 


252 


ELECTRICAL EQUIPMENT 


may be used as the main source of ignition current; as this interrupter 
makes instantaneous contact only at tlie moment the spark is 
required in the cylinder, the battery otherwise being on open circuit. 

Q. How can the life of such a battery be prolonged? 

A. By connecting two or more sets of four cells each in series- 
multiple, i.e., each group of four is connected in series to give the 
required voltage, and the positive and negative terminals of each 
group are connected together. The amount of current then drawn 
from each cell is only one-half what it would be if a single set of cells 
were employed, or one-third what it would be where sets are in 
series-multiple, and so on. 

Q. When a set of four dry cells will last a certain length of time, 
why is it that adding extra cells in series, for example, a six=cell 
battery, will not last longer? 

A. The amount of current drawn from the cells when the cir¬ 
cuit is closed depends upon the voltage of the entire series, and the 
greater the total voltage the larger the volume of current, in accord¬ 
ance with Ohm’s law. Consequently, the six-cell battery will not 
last so long as the four on the same service. 

Q. Why is it not good practice to connect an old set of four 
cells in series=multiple with a new four=cell battery, or groups of 
uneven numbers in the same manner, as for instance, three in one 
and four in another? 

A. The new cells will have an output of twice that of the old 
ones, so that when the circuit is closed they will discharge through 
the latter until the amperage of all is equalized. Where uneven 
numbers are used in groups in series-multiple connection, the volt¬ 
age of the larger will be superior to that of the smaller, and a similar 
action will take place on open circuit so that in a short time the 
maximum potential of the battery will be that of the weakest group. 

Q. Why should one cell much lower than the others never 
be included in a dry=cell battery? 

A. For the reason just given above, as well as the fact that an 
exhausted cell increases the resistance of the battery as a whole 
and decreases the current. 

Q. Why will the dry=cell battery used on a dual ignition 
system not run the engine satisfactorily for any length of time when 
the magneto is not in proper working order? 


ELECTRICAL EQUIPMENT 


253 


A. Because the interrupter, or contact breaker, of the magneto 
is of the closed-circuit type, thus drawing current continuously, 
except when the points open to break the circuit and induce a high- 
tension current in the secondary of the coil. In a system of this type, 
the dry cells are intended only for starting purposes. 

Q. Why can a modern battery system not be used with dry 
cells? 

A. Because the interrupter is of the closed-circuit type, similar 
to that of the magneto, and the demand for current (usually about 3 
amperes) is practically constant. It is not so much the amount of 
current required that affects the dry cells, as the fact that they are 
almost constantly on closed circuit, so that there is no opportunity 
for the depolarizing agent to work. This demand on the storage 
battery of the starting and lighting system (usually of 80- to 120- 
amj)ere-hours capacity) is negligible. At a 3-ampere discharge 
rate, the larger battery when fully charged and in good condition 
would be capable of giving practically forty hours of continuous 
service. Under the same conditions, new dry cells would not pro- 
x'ide efficient ignition for more than an hour. 

Q. Does the voltage, as well as the amperage, of the dry 
cell fall off on closed circuit? 

A. The voltage is affected very slightly; a cell that is practically 
exhausted will show almost 1| volts so that a voltmeter test is no 
indication of the condition of the cell. 

FORD IGNITION SYSTEM 

While a great many of the causes of missing or breakdown, in 
the ignition system covered by the foregoing queries, apply to a great 
extent to all cars, such as loose wires, short-circuits and the like, the 
J^'ord system is distinctive. It is based on the same fundamental 
principles, of course, but it has many features not to be found on 
other cars so that there are causes of failure that could never be 
readily determined by experience gained on other makes of machines, 
though long handling of ignition apparatus would naturally be of 
great assistance. In working on the Ford ignition system it must be 
borne in mind that it is a combination of the old-time battery system 
with a modern generator as the source of current supply, so that the 
many defections due, in the earlier days to the dry battery, are now 
lacking. 


254 


ELECTRICAL EQUIPMENT 


Q. Of what does the Ford ignition system consist? 

A. A multipolar alternating-current generator (magneto) 
built integral with the flywheel; a primary, or low-tension timer, in 
which a roller makes contact with the four stationary segments in 
the housing; four vibrator coils, one for each cylinder, plus the usual 
number of spark plugs and connections in the primary and second¬ 
ary circuits. 

Q. Is the Ford ignition system efficient and reliable, or is it 
advisable when much trouble is experienced with it to replace it 
with any of the numerous accessories and complete ignition systems 
that are claimed to be improvements? 

A. While there are many ignition systems the parts of wdiich 
are made with greater precision, and some in wdiich the design and 
particularly the accessibility of the important essentials are superior, 
experience has proved the Ford system to be both efficient and 
reliable. With proper care, there should never be any necessity for 
replacing it with any system made by an accessory manufacturer, or 
for adding to it any one of the legion of devices advertised as 
improvements on it. 

Timer 

Q. What are some of the commoner causes of failure of the 
Ford system? 

A. One of the most frequent is due to the timer and is caused 
by failure to lubricate it. Contrary to the usual practice, which is 
to prevent oil getting on the contacts of a timer as it tends to insu¬ 
late the latter, the Ford timer requires plenty of oil, and should be 
lubricated every day. There is no fear of giving it too much oil as 
the excess will leak out of the housing; it will continue to operate 
satisfactorily even though flooded with oil, while the slightest lack 
of it will cause trouble. 

Q. What is the nature of the trouble caused by the timer? 

A. If not oiled at regular intervals, it will cause missing of 
various cylinders, and those that do fire will be late, as if the ignition 
were fully retarded, so that the motor develops very little power. 
An accumulation of gummed oil and dirt will produce a similar 
result. The tinier housing should be taken ofl* and the contacts 
cleaned; the roller contact also should be cleaned by squirting gaso¬ 
line over it and wiping over well. 


ELECTRICAL EQUIPMENT 


255 


Q. Will lack of oil have any other result? 

A. Besides the missing, usually most noticeable at higher 
speeds, failure to lubricate will result in very rapid wear of both the 
roller and its track (contacts in the stationary housing) so that its 
operation will soon become unsatisfactory, even though subsequently 
kept oiled. 

Q. What are some other causes of faulty operation of the 
timer (generally referred to as a commutator)? 

A. Weakening of the spring which holds the roller against its 
track will cause missing at low speeds, while a loosening of the spring 
which holds the timer housing in place is liable to cause erratic firing 
at all speeds. This spring is held by a single cap screw passing 
through the breather tube, which serves also as an oil filler for the 
crankcase. At its inner end it has a small boss which fits in a cor¬ 
responding depression in the hub of the timer housing. This is the 
only thing that holds the latter in place. The loosening of this cap 
screw is liable to let the housing drop out of place sufficiently to pre¬ 
vent the roller making contact with all of the segments. 

Q. Does the weather have any effect on the operation of the 
timer? 

A. Unless precautions are taken to lubricate it properly, cold 
weather will make starting difficult. This is due to ordinary lubri¬ 
cating oil becoming congealed in the housing, thus preventing the 
roller from coming into good contact with the segments. An indi¬ 
cation of this sometimes is that the motor will fire only on two or 
three cylinders for several minutes after being started and will there¬ 
after fire regularly, the oil then having become liquefied again. 

Q. How can the timer be removed? 

A. Take out cotter pin from end of rod which attaches it to 
the spark-advance lever on the steering column, and detach this rod. 
Loosen cap screw passing through breather pipe on top of the timing 
gear cover. This releases the spring which holds the timer housing 
in place, and the latter can be easily removed. To remove roller 
contact, unscrew lock nut, withdraw steel brush cap and drive out 
the retaining pin. The brush can then be lifted from the cam¬ 
shaft. In replacing it, care must be taken not to alter the timing 
of the ignition. The upper contact of the housing represents cylinder 
No. 1, and the exhaust valve of that cylinder should be closed when 


256 


ELECTRICAL EQUIPMENT 


the brush points upward. This may be determined by removing 
the valve mechanism cover and noting the operation of the valve 
in question. 

Q. If parts show much wear, what should be done? 

A. Replace them; as they cost so little that it is far less expense 
to put in new parts than to attempt to make old ones serve by 
truing them up. 

Q. When examination reveals gummed oil and the weather is 
cold, what should be done? 

A. Clean out the housing and the roller-contact parts with 
gasoline, and use a mixture of | kerosene and f lubricating oil in the 
timer, as long as the weather is cold. 

Q. What other causes of trouble with the timer are more or 
less common? 

A. Short-circuiting of the primary wires which lead to the 
timer, or the loosening of these wires at the terminals on the housing. 
The position of the timer is such that the insulation of these wires 
is subjected to considerable wear by reason of the movement of the 
housing in advancing and retarding the time of ignition. The best 
method of remedying this is to replace the entire set of primary wires. 

Vibrator Coils 

Q. Is irregular firing likely to be caused by any other part of 
the system than the timer? 

A. The vibrators of the induction coils may get out of adjust¬ 
ment and cause either erratic firing, or missing of one or more cylinders 
altogether, in case one or more vibrators cease to operate. 

Q. How can this be determined? 

A. Run the motor slowly and watch the action of the vibrators; 
they should act regularly and with the same rapidity in each case, 
any stuttering or hesitation indicating either poor adjustment or 
points in poor condition. 

Q. How can the vibrators be utilized to determine which 
cylinder is missing, where the cause lies in some part of the system 
other than the vibrators themselves? 

A. Hold one vibrator down at a time with the finger; if the 
remaining three cylinders fire regularly, the one represented by the 
vibrator being held out of action is the one at fault. The cylinder 
can always be located quickly by holding down each vibrator in turn. 


ELECTRICAL EQUIPMENT 


257 


Q. When the cylinders do not all fire regularly, but there is 
no perceptible difference between the action of the vibrators, how 
can the cylinder, or cylinders, at fault be determined? 

A. Hold down the vibrators in pairs, taking first Nos. 1 and 4, 
and then Nos. 2 and 3. This will cause the engine to run on two 
cylinders at a time, and any difference between the operation of the 
two pairs or between members of each pair will be apparent. 

Q. What is the firing order of the Ford motor? 

A. 1-2-4-3. 

Q. How are the coil vibrators adjusted? 

A. The usual method is to turn the adjusting screw up until 
the vibrator stops buzzing; then turn the screw down again very 
slowly until the points just come together and the firing of that 
cylinder becomes regular; then give the screw an extra quarter-turn 
down, and lock in place. 

In adjusting K-W coils, it is important to see that the little 
flat-cushion spring just underneath the vibrator bridge works back 
and forth every time the points make and break contact. This can 
be determined by taking the coil unit out of the box and holding 
the vibrator up to the light; press down the vibrator and observe 
the action of the cushion spring. It is important to adjust all the 
units alike or the motor will not develop its full power. 

Q. What is the effect of adjusting so that the contact points 
are too far apart; too close together? 

A. If too far apart, the cylinder will not fire regularly or with 
its usual power. If too close together the current is likely to arc at 
the contact points, thus preventing the breaking of the circuit when 
the armature is drawn down, burning the points themselves, and 
sometimes putting the coil out of action entirely. 

Q. Does the vibrator adjustment affect starting? 

x\. When the points are too close, more current is required to 
‘hnake and break” the contact between them, and the motor must 
be turned over that much faster. For the best adjustment, the 
points should barely touch. If the adjustment is too light, they may 
not do this and a miss at that cylinder will result. 

Q. If the vibrator buzzes constantly, what is the trouble? 

A. There may be a short-circuit at the timer or in the wire 
leading from that coil to it, or the coil itself may be defective. One 


258 


ELECTRICAL EQUIPMENT 


of the first symptoms of a defective coil is the buzzing of the vibra¬ 
tor, with no spark at the plug. 

Q. How can a defective coil be determined? 

A. To make certain that the cause is in the coil, change the 
location of the units in the coil box. If another unit acts the same 
when substituted for the one giving trouble, the fault is not in the 
coil but in some other part of the system. Should the coil that is 
shifted, however, act the same in its new location, and the one that 
takes its place operates properly, the coil itself causes the trouble. 

Q. When there is an unusually heavy or ‘Taf’ bluish spark 
at the contact points, what is the cause? 

A. The current may be arcing at the points, due to their being 
adjusted too closely; or the condenser may have broken down. To 
make certain that the condenser has failed, disconnect the secondarv 
cable from the spark plug and hold the terminal about inch away 
from the metal end of the plug. If the condenser has failed, the 
spark occurring at this gap will be irregular. 

Q. What will happen if the contact points are allowed to 
become pitted and ragged, due to the burning effect of the current? 

A. They are liable to stick together and cause unnecessary 
difficulty in starting or occasional missing when running. They 
should be trued up with a very fine fiat file or with an old piece of fine 
sandpaper. Never use emery. 

Q. When the vibrator points burn badly in a very short time, 
what is the cause? 

A. The owner of the car has probably replaced the original 
vibrators with cheaper substitutes having nickel or German-silver 
contact points. Nothing but platinum or platinum-iridium con¬ 
tacts will give satisfactory service, so that new parts from the makers 
should be installed. 

Q. When the engine will suddenly lag and pound, what is the 
cause? 

A. An intermittent short-circuit in the wiring or at the com¬ 
mutator. The pounding is caused by the premature explosion of 
the charge against the rising piston. The vibration causes the short- 
circuit to occur at some times, and not at others, so that the engine 
will run regularly for a few minutes and then pound again, until 
the movement once more temporarily eliminates tlie cause. 


ELECTRICAL EQUIPMENT 


259 


Q. With all the vibrators properly adjusted and the timer 
and wiring in good condition, what is the cause of irregular firing? 

A. Provided the spark plugs are all in good condition, points 
not too far apart, etc., this is frequently caused by the top of the coil 
box coming loose. The coil units are provided with brass-strap 
terminals on the bottom of the wooden casing of the coil, and these 
terminals make contact wdth similar straps in the bottom of the coil 
box on the dash.. They depend for good contact on the pressure 
exerted by the cover of the box, which must always be kept tightly 
snapped on. 

Q. When missing is not traceable to any of these causes, 
what is likely to be the cause? 

A. Something outside of the ignition system, such as a weak- 
vah^e spring, or a valve improperly seating, due to some other cause. 
Loss of compression at the cylinder-head gasket: run a little lubri¬ 
cating oil along the edge of the gasket and note wdiether bubbles 
appear. Replace wdth a new gasket if any leakage is apparent. 

Magneto 

Q. How does the Ford magneto differ from the regulation 
type? 

A. The magnets are revolved instead of the armature; it has 
sixteen field poles and armature coils, and it revolves at crankshaft 
speed to fire a four-cylinder motor. It is not timed to the motor 
the same as an ordinary magneto, which is coupled to the camshaft, 
or other half-time shaft, and the distributor of which must rotate 
synchronously with the motor. 

Q. Of what does it consist? 

A. Two discs, one carrying sixteen magnets with their poles 
pointing outward, and the other sixteen coils of strap copper on oval 
cores, all of the coils being connected in series. The disc carrying 
the magnets is rotated by the flywheel to which it is attached, while 
the other disc is attached to the crankcase, and remains stationary. 
One end of the coil wdnding of the magneto is grounded on the support¬ 
ing disc carrying the coils, while the other is led to a terminal which 
extends through the flywheel housing. A cable from this terminal 
or binding post, supplies current to the coils. 

Q. Is it ever necessary to remagnetize the magnets of the 
field, and how can it be done? 


260 


ELECTRICAL EQUIPMENT 


A. Unless they have become demagnetized, due to some out¬ 
side influence, it is rarely necessary to touch the magnets. 

Q. How can they become demagnetized by an outside force? 

A. The attachment, by mistake, of a storage battery to the 
magneto terminal will send a current through the coil windings in 
the opposite direction, and will demagnetize them. When this 
happens, it is not advisable to attempt to remagnetize the old 
magnets, as it is much cheaper and quicker to replace them. The 
new set is supplied mounted on a board in exactly the position they 
should be installed. 

Q. How can the magneto be dismounted? 

A. To do this, it is necessary to remove the power plant from 
the car. The radiator must be taken off by disconnecting its stay 
rod and taking out the two holding bolts at the frame, after 
uncoupling the hose connections. Remove the dash and loosen the 
steering-post bracket, fastened to the frame, permitting the dash and 
steering gear to be lifted off as a unit (wires having first been dis¬ 
connected) ; take out bolts, holding front radius rod in socket under¬ 
neath the crankcase; remove four bolts at the universal joint; remove 
pans on either side of cylinder casting; disconnect feed pipe from 
carburetor, and exhaust manifold from exhaust pipe, by unscrewing 
large brass nut; remove the bolts which hold the crankcase arms to 
the frame at the side; then pass a rope through the opening between 
the two middle cylinders, and tie it in a loose knot; through the rope 
pass a 2 by 4 timber or a heavy iron pipe about ten feet long; with a 
man at each end of this and a third at the starting crank, the 
whole power plant can readily be lifted out; then remove the crank¬ 
case and transmission cover, and take out the four cap screws that 
hold the flywheel to the crankshaft. This gives access to every part 
of the magneto mechanism. To take out the old magnets, simply 
remove the cap screw and bronze screw which holds each in place. 
When reassembling the magneto, great care must be taken to see 
that the disc or plate carrying the magnetos revolves them exactly 
^ inch of the core faces of the coils. 

Q. How can it be determined whether the magnetos are at 
fault or not? 

A. Whenever there is a partial failure of the current, remove 
the binding post by taking out the three screws which hold it in 


ELECTRICAL EQUIPMENT 


20)1 


place. Clean out any dirt or foreign matter that may have accumu¬ 
lated under the contact spring. If this does not materially improve 
the running, test by comparing with battery ignition. Connect 
one terminal of a six-volt storage battery to the battery terminal 
on the coil box (a battery of four or five fresh dry cells will serve 
equally well for a short test run), and ground the other terminal of 
the battery on the frame of the car, making certain that good electrical 
connection is made. Run the engine at different speeds on the 
magneto, and, while running, throw the switch over suddenly to 
the battery point; any decided acceleration in the speed will indicate 
that the battery is supplying a much better current for ignition, 
and that the magneto is at fault. If used for any length of time for 
testing, a dry-cell battery will not give equally accurate results, as 
the cells are likely to run down very quickly, and the firing will then 
be better on the magneto, even though the latter be weak. 

Q. When the engine suddenly fails to fire altogether, what is 
likely to be the cause? 

A. The cable leading from the binding post on the magneto 
has dropped off, either at the latter or at the coil; or some piece of 
foreign matter has come between the contact spring attached to the 
binding post and its contact. 

Q. When the magneto gradually gets weaker and weaker in 
a car that has seen a great deal of service, is it certain that the 
magnets have weakened? 

A. Not necessarily; the adjustment of the bearings may be 
permitting the disc carrying the magnets to revolve further away 
from the armature coils than intended. Any increase in this dis¬ 
tance, even though small, will have a decided effect on the output of 
the magneto. 

GENERAL CAUSES OF IGNITION FAILURE 

Q. When the motor stops very suddenly without any apparent 
cause, what is likely to be the cause of the trouble? 

A. A break in the current-supply circuit of the ignition system, 
or sudden failure of the ignition current, due to any other cause. 

Q. In how many different ways may this occur? 

A. A feed wire from the battery may part from its terminal, 
either at the battery or at the coil; the ground wire may become dis- 


262 


ELFX^TIUCAL EQUIPMENT 


connected at either end; in a dual system, the primary cable from the 
magneto to the coil may become disconnected, either at the magneto 
or at the coil; the secondary cable from the coil to the magneto 
distributor may loosen and drop off, either at the coil or at the 
magneto; this secondary cable may become grounded between the 
coil and the magneto; the switch may have loosened up, through 
vibration, and may jar open; the magneto may have become grounded 
internally, so that no current is delivered to the outside circuit. 
The magneto cam may have loosened up on its shaft, so that it no 
longer revolves with the latter, and, consequently, does not open 
the contact points in the breaker box. The primary cable from the 
magneto to the coil may have become grounded on the frame or 
short-circuited on another cable, due to wear from chafing, thus 
preventing the current from reaching the coil. In a dual system, 
the entire system may have become grounded through the metal 
of the dry cells coming in contact with the metal battery box or 
other metal part connected to the chassis of the car. 

Q. Do the foregoing constitute all of the possible causes for 
a sudden failure of the ignition system? 

A. No brief resume could possibly include all of the causes 
that may exist for a stoppage of this kind, but they include probably 
more than 90 per cent of all the commoner causes of such a failure, 
and, either as given above, or in some modified form of the same 
condition, will be found to represent by far the greater part of all 
the causes of sudden stoppage. 

Q. Of the causes given above, which are the most likely, in 
the order of their usual occurrence? 

A. The loosening of a battery connection at the terminal or 
at the coil, or of a magneto and coil connection at either end; ground¬ 
ing or short-circuiting of either the primary or secondary main 
connection between magneto and coil, that of the secondary being 
more frequent owing to the high-tension current it carries. Ground¬ 
ing of the dry cells in the battery box; loosening of the switch so that 
it jars open. With the exception of the grounding of the primary 
or secondary cable between the magneto and the coil, all of the 
above are the direct result of vibration and jarring. In old four- 
cylinder motors, vibration is constant, and at times very severe, so 
that attention should first be directed to searching for loose con- 


ELECTRICAL EQUIPMENT 


2R3 


iiections, as unless tightened up at intervals, they are very likely 
to shake off. Internal grounding of the magneto or loosening of the 
breaker-box cam, so that the interrupter does not operate; these are 
rarer causes of trouble, and a search for them should be deferred 
until after the commoner causes mentioned above have been 
thoroughly investigated. 

Q. Where all connections have been tightened up without 
overcoming the trouble, how can the other possible causes of stop= 
page be eliminated, in tracing the real seat of the failure to run? 

A. See that the dry batteries of a dual system are not touching 
any metal; inspect the magneto breaker box while another person 
slowly turns the motor over by hand, so that the operation of the 
interrupter may be noted. If working properly, disconnect the 
secondary cable from the magneto to the coil, and with the motor 
running, hold its terminal J inch away from the coil connection. 
In case there is no fault here, a bright spark will result at the gap. 
Note whether holding the cable away from the motor has been 
responsible and whether, when it is dropped back on the motor again, 
sparking occurs at any point along its length between the cable and 
the metal of the motor. Disconnect the primary cable from the 
magneto to the coil, and, with the motor running, wipe its end on 
the primary terminal of the coil; sparking should result if there is 
no break in the cable. Take the same precaution in putting it back 
as with the secondary cable to see that it is not grounding at some 
place along its length where it touches the motor. No visible spark 
will be produced in this case, but the condition of the insulation of 
the cable itself should be the best indication of this kind. Bend 
the wire along its length to detect any possible breaks in the copper 
wire under the insulation. Disconnect the ground cable from the 
coil to the magneto, and, while the motor is running, hold it close 
to either the magneto or the coil terminal; a high-tension spark will 
result if the cable is all right. Note, while the motor is running, 
whether there is any sparking at the safety gap, on the magneto 
itself, if on the high-tension type, or on the coil of a dual system. 
Note whether the primary and secondary cables cross each other, 
and whether there is any sparking between the two while the motor 
is running. Inspect the ends of all stranded cables carefully, and 
see whether one or more of the fine wires have not broken through 


204 


ELECTRICAL EQUIPMENT 


the insulation and become bent over, so as to ground the cable on 
some adjacent metal. 

Q. Is a sudden stoppage of the motor likely to be due to any 
cause other than a failure of the ignition system? 

A. One possible cause is the sudden and complete stoppage of 
the carburetor spray nozzle, but, even in this case, the failure of the 
motor will not be so sudden nor so complete as where the ignition 
current has been cut off, as the motor will continue to fire, for a few 
revolutions on what fuel mixture remains in the manifold. There 
is practically no other cause for the motor suddenly stopping. 

Q. When, instead of stopping completely, the motor will fire 
regularly for a few minutes, hitting on all cylinders, and then begins 
to miss spasmodically, how can it be determined whether the fuel= 
supply system or the ignition is at fault? 

A. The fact that, under such circumstances, the motor will 
fire regularly for a little while and then miss very badly, and, a few 
minutes later again take up its operation smoothly, is usually an 
indication that the ignition system is working properly, but that at 
intervals there is a failure of the fuel supply. One of the commonest 
causes of this is the exhaustion of the main supply of gasoline in the 
tank. On the last half-gallon or so of fuel there is no longer a regular 
supply to the carburetor, with the result that, with the motor run¬ 
ning at speed, what gasoline is in the carburetor is practically 
exhausted in a few minutes. During this period, however, the motor 
will continue to run regularly. As it lowers the level in the car¬ 
buretor float chamber, an insufficient supply is drawn through the 
nozzle and the motor misses badly, and slows down almost to the 
stopping point. This permits a new supply to fill the carburetor, 
and the motor once more runs properly. It is the extremely inter¬ 
mittent nature of the firing, with first one cylinder missing and then 
another while the carburetor is refilling itself from what little gaso¬ 
line remains in the tank, that makes this appear very much as if it 
were due to failure of the ignition. Under conditions such as this, 
always inspect the fuel supply first. With an ample supply of gaso¬ 
line in the tank, a partial clogging of the spray nozzle of the carbu¬ 
retor, due to some obstructions which is intermittently drawn up 
into it by the suction and again drops back, will give exactly the same 
symptoms of ignition trouble. 


ELECTRICAL EQUIPMENT 205 

Q. Are symptoms of this nature ever due to a fault in the 
ignition system? 

A. They will result at times from the use of a set of drv cells 

1/ 

that is almost exhausted. The storage battery also acts in a similar 
manner. Both the dry cell and the storage battery recuperate very 
rapidly even when practically exhausted, so that they will often 
provide sufficient current to run the motor properly for a very 
short time, will then cause it to miss badly, and shortly afterward 
again run regularly. If, when the switch is thrown over to the 
magneto, the motor runs smoothly and continuously, there is no 
doublt that the battery is at fault, and this may be verified by test¬ 
ing the cells with a pocket ammeter. Should they show much less 
than eight amperes on test, they are the cause of the trouble and 
should be discarded. This may also be due to the use of a storage 
battery that is practically exhausted, though it would be extremely 
bad practice to allow a storage battery to get this low. Test with 
the voltmeter: if the cells show 1| volts each or less they are badly 
in need of charging, and if they will not run the motor properly, 
should be immediately recharged from an outside source of current. 

Q. What is meant by ‘‘pre=ignition”, and what causes it? 

A. When the charge in the cylinder is ignited before the passing 
of the spark at the spark plug, it is said to be ‘^pre-ignited”, i.e., fired 
in advance of the proper time. As a result, the force of the explosion 
is partly exerted against the rising piston, as is evidenced by a 
heavy pounding accompanied by a decrease in the power. The 
cause is usually an accumulation of carbon in the form of a deposit 
on the piston head and results from excessive lubrication. The 
surplus oil finds its way into the combustion chamber and is burned. 
This condition is further aggravated by running with an over-rich 
mixture. If the motor is allowed to run very hot, these carbon 
deposits become incandescent, so that the fresh mixture is fired the 
moment it comes in contact with them. In some cases this becomes 
so bad that the motor cannot be stopped without shutting off the 
gasoline supply. 

Q. How can the pounding caused by pre=ignition be distin= 
guished from other internal noises, such as those produced by a 
loose crankshaft or crankpin bearing? 

A. Pre-ignition takes place only after the motor has been 


2m 


ELECTRICAL EQUIPMENT 


running long enough to become very warm and with the throttle 
opened to any extent the pounding is very violent, jarring the whole 
chassis. The noise produced is distinctive and can be identified 
readily once it has been experienced. Unless very loose, a bearing 
noise will practically disappear if the motor is allowed to idle very 
slowly and will always increase in proportion to the load, becoming 
very severe when climbing a hill. 

Q. How can the condition which causes it be remedied? 

A. By removing the carbon deposits. In many late-model 
engines this can be done most readily by removing the cylinder 
heads, usually a single casting. The carbon may be burned out 
with the oxygen-gas fiame now in common use or it may be loosened 
by the use of kerosene in the motor. After the motor has run long 
enough to become hot, shut off the gasoline supply gradually, mean¬ 
while feeding kerosene through the auxiliary-air inlet of the carbu¬ 
retor until the motor is running on kerosene alone; feed an excess of 
the latter and the carbon will be loosened and blown out through 
the exhaust. 

Q. When a single cylinder continues to miss regularly, all 
the others running properly, and inspection shows every part 
of the ignition system to be in good condition, what is likely to 
be the cause? 

A. Failure of its valves to operate properly. Either the inlet 
or the exhaust valve is not opening, or is sticking open (the result 
will be the same in either case). This may be caused by a weak 
valve spring, a bent valve stem, derangement of the valve tapper, 
so that it does not strike the valve-stem end, or by a piece of foreign 
matter, such as a piece of carbon, lodging on the seat of the valve, 
so that the latter cannot clos^. Another, though rarer cause, is a 
leak in the manifold, close to the inlet valve of the cylinder in question. 
This permits an excessive amount of air to be drawn into that par¬ 
ticular cylinder, so that the charge is too weak to fire. In any of the 
above cases, the result is that fuel either does not get into the cylinder 
or it is exhausted before it can be fired, as with every part of the 
ignition system working properly, the only thing that can cause a 
cvlinder to miss is lack of fuel. 

Q. Mention one of the causes of irregular firing that is seldom 
suspected, except by those who have experienced it previously? 


ELECTRICAL EQUIPMENT 


267 


A. Excess oil finding its way into the combustion chambers in 
such quantities that it covers the spark-plug electrodes, thus pre¬ 
venting a spark from jumping the gap. The oil, particularly when 
fresh, is an excellent insulator and, if mixed with carbon so that it 
conducts the high-tension current, it does so without permitting the 
formation of a spark. Owing to the viscosity of heavy lubricating 
oil, it clings to the spark-plug points and when they are as close 
together as they should be (A inch), it will often bridge the gap for 
some time, despite the vibration and succeeding compressions in the 
cylinder. This fault is particularly difficult to locate when not 
suspected, as jolting over a rough piece of road will shake the plug 
points free and the engine will fire regularly, again missing inter¬ 
mittently when on smooth going once more. When confined to one 
cylinder, it is usually an indication that the cylinder wall is scored, 
or that the lubricating-oil feed to that cylinder is deranged. 

Q. Mention a rare cause of what appears to be ignition 
failure? 

A. When a motor has been taken down and all its working 
parts thoroughly cleaned with gasoline or kerosene, it will sometimes 
be found next to impossible to start it. The explosions are very 
weak and erratic, and the engine does not generate sufficient power 
to run more than a few revolutions at a time. The trouble has every 
indication of being due to a derangement of the ignition system and 
looks particularly as if it might be faulty timing, caused by misplacing 
the spark-plug leads. In one case of this kind experienced by the 
writer, all the spark plugs and wiring were renewed, fresh batteries 
]:)ut in, and every part of the ignition system checked by three 
experienced garage men, but the motor could not be made to run. 
The trouble was finally overcome by Taking out the spark plugs and 
injecting two or three ounces of the heaviest cylinder oil into the 
combustion chambers. The motor was old and well-worn so that 
the pistons were loose; the cleaning process left all these parts wet 
with kerosene and there was enough of the latter left in the crank¬ 
case to thin out the fresh lubricating oil considerably. As a result 
there was no compression, and the force developed by the explosion 
was not sufficient to turn the motor over for more than a few revolu¬ 
tions; what little oil was splashed up ’by this was too thin to seal 
the space between the pistons and cylinders so that most of the 


268 


ELECTRICAL EQUIPMENT 


power generated by the weak explosions leaked past the pistons. 
Trouble of this nature is most likely to occur in old and well-worn 
motors, and will sometimes result from excessive priming with gaso¬ 
line, i.e., squirting gasoline in through the petcocks or spark-plug 
holes, as this washes all the lubricating oil from the cylinder walls 
into the crankcase and thins the oil in the latter. 

Q. When intermittent failure of the ignition is thought to be 
due to faults in the wiring which cannot be detected by an ordinary 
examination, how can the trouble be found most readily? 

A. Fit a handy length of cable—one that will span practically 
any two points in the ignition system—with spring-clip terminals. 
Disconnect each wire in turn, and substitute for it this length of 
cable as a temporary connection; satisfactory operation with the 
latter indicates that the wire it replaces is at fault. 



1 


. * 




I \ 








T 



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< «. • 











TYPICAL LIGHTING AND IGNITION GENERATOR, 1917 DELCO TWO-UNIT SYSTEM AS 
USED ON COLE, OAKLAND, AND OLDSMOBILE EIGHT-CYLINDER MODELS 

Courtesy of Dayton Enginecriny Laboratories Company, Dayton, Ohio 






ELECTRICAL EQUIPMENT FOR 

GASOLINE CARS 

PART IV 


ELECTRIC STARTING AND LIGHTING 

SYSTEMS 

GENERAL FEATURES 

Fundamental Characteristics. In the introduction to ele¬ 
mentary electric principles, no attempt has been made to go beyond 
simple theory as applied to the generation of electric currents, the 
operation of electric motors, circuits and the auxiliary devices 
required by the lighting and starting systems employed on the 
automobile. A very large part of the theory of electricity and 
electrical action as given in the majority of textbooks is omitted 
altogether for the sake of clearness, only that part of it which bears 
directly on the subject of electrical equipment of the automobile 
being retained. In the presentation of the latter, a somewhat 
different method of handling the subject has been followed, par¬ 
ticularly with a view to making it appeal to the practical man by 
citing examples and comparisons, the force of which is at once clear. 
The man whose time for study is limited has no opportunity to go 
into all branches of electrical phenomena, so that the subject is 
presented in the briefest and most practical manner. 

Considering that the practical application of electric lighting 
on the automobile dates back to 1910 only and electric starting to 
1912 models, in which year but one make of car was fitted with a 
complete system as regular equipment, there are a number of differ¬ 
ent types in use. Each is characterized by varying features of 
design in the generators, motors, and auxiliary devices. In many 
instances these are slight, in others they are radical, but in every 
case they merely represent a different application of the fundamental 
principles given in the introduction. Since they must first pass the 
test of practical use before being adopted by the automobile manu¬ 
facturer, they all operate successfully. But, that they all do not 



270 


ELECTRICAL EQUIPMENT 


operate equally well, or, to put it better, all do not continue to show 
the same high degree of efficiency and reliability in service, goes 
without saying. Owing to the lack of standardization that pre¬ 
vails, it is necessary to become familiar with each system. A brief 
analysis of each of the systems in general use accordingly is given 
here, and it will be found valuable for reference. 

VARIATIONS OF OPERATING UNITS AND WIRING PLANS 

Principal Differences. Before taking up the different systems 
in detail, an outline of the chief points on which they vary is given 
as an aid in distinguishing them when found in service on the various 
makes of automobiles of which they form a part. Electrical sys¬ 
tems as a whole may be divided into two general classes. These 
are the single-unit and the two-unit types. 

Single-Unit Type. The first type is characterized by the 
employment of a dynamotor —a single unit with generator and 
motor windings on the same armature and fields connected to inde¬ 
pendent commutators at each end of the armature, as in the Delco, 
(in some models, two concentric commutators at the same end) or 
to the same commutator, as in the Dyneto. The single-unit type 
is greatly in the minority, the two makes cited being the chief 
exponents of it, though both of them are also built in the double¬ 
unit type as well. When the ignition distributor is incorporated in 
the generator, as is now very generally the case, the single-unit 
types incorporate in one machine the three chief electrical func¬ 
tions required on the automobile, viz, charging the storage battery, 
turning the engine over to start, and distributing the ignition current. 

Two-Unit Type. Owing to the difficulty of efficiently com¬ 
bining in one machine two functions so widely separated as the 
generation of a constant charging current of a value rarely exceed¬ 
ing 20 amperes, and the utilization of currents up to 350 amperes, 
such as are required for starting, the majority of systems are of the 
two-unit type. The latter also is generally favored owing to its 
greater convenience of installation, as the dynamo must run either 
at motor speed, or at 1J times that, while it is necessary to gear the 
starting motor to the engine in the ratio of 30 or 40 to 1. As the 
term implies, an independent unit is employed for keeping the 
storage battery charged, lighting the lamps (when running), and 


ELECTRICAL EQUIPMENT 


271 


distributing the ignition current, while a second unit is installed 
solely for the purpose of turning the gasoline engine over to start. 

Single=Wire and Two=Wire Systems. The difference between 
these is pointed out in detail in the section on Wiring Diagrams, 
Part IV. Owing to its greater simplicity of installation, reduced 
cost for wiring, and the greater ease with which faults may be 
located, the single-wire system is largely in the majority. In fact, 
there are only one or two examples of two-wire systems in general 
use, of which the Bijur, as employed on the Packard, Jeffery, and 
other cars, may be cited as an instance. In the gradual approach 
to standardization that is being made each year, the number of 
cars on which the single-wire system is employed is constantly 
increasing. But differences will be found in these single-wire sys¬ 
tems as well, some employing the frame of the car for the positive 
side of the circuit, and others for the negative. This must be borne 
in mind when testing for faults with the volt-ammeter. 

Comparison of Systems. While inherently more dangerous, 
experience has demonstrated that the fire hazard with the single¬ 
wire system is more a matter of proper installation than of the com- 
})arative merits of the systems themselves, and quite a number of 
manufacturers who adopted the two-wire system at the outset have 
later become converts to the single-wire system. In fact, while the 
Society of Automobile Engineers has not adopted the latter as 
recommended practice up to the present writing, although the sub¬ 
ject has been under investigation for almost three years, the major¬ 
ity of automobile makers have taken it as their standard construc¬ 
tion, and it seems more than likely that the others will do so before 
long. Considerations of economy demand this on the lower-priced 
machines, as the cables employed are so expensive as to make a 
substantial difference in the cost per car for the electrical equipment 
where the single-wire standard is employed. It does not follow 
from this that where the maximum of safety and efficiency are 
to be attained regardless of cost, the two-wire system is always 
employed, as, after experiencing considerable difficulty with it, the 
makers of the Pierce-Arrow adopted the single-wire system. The 
Packard, on the other hand, employs the double-wire system, and 
the advantages in simplicity of the single-wire may be noted by 
comparing the Packard installation, as shown in Fig. 144, 



272 ELECTRICAL EQUIPMENT 

with the Delco single-wire system, Fig. 145, which is employed on a 
great number of cars. Comparison cannot be made exactly on the 


Fig. 144. Wiring of Packard (Bijur) Two-Unit, 
Courtesy of Packard Motor Car 

same basis in these two installations, however, as the Packard is 
what is known as a two-unit system, i.e., the generator and the 
electric starting-motor are independent, while the Delco is a com- 
























































































ELECTRICAL EQUIPMENT 


273 


bination generator, motor, and ignition unit. Moreover, the Pack¬ 
ard has several additional lamps, being fitted with double bulb 



Two-Wire Starting and Lighting System (1916 Model, Six-Cylinder) 

Company, Detroit, Michigan 

lieadlights and side lights, which are not present in the Delco installa¬ 
tion; but even omitting these considerations, it will be seen that the 
single-wire system has the advantage of simplicity in a marked degree. 






































































HORN BUTTON 


274 


ELECTRICAL EQUIPMENT 



Z-I 

o< 

ao 

u. lu 
Ui O 

h~ 5 

<t- 

Cc 

ui <f 
O-W 
O'/' 


CSf> 

<uf 

lU ^ 
^2 


za 


5< 


OCi 


CTH 


O t/l 


i^ig. 145. Wiring of Delco Single-Unit, Single-Wire System 
Courtesy of Dayton Electric Laboratories, Inc., Dayton, Ohio 


















































ELECTRICAL EQUIPAIENT 27n 

METHODS OF REGULATION 

Necessity for Control of Generator Output. In the section on 
Generator Principles, Part I, mention has been made of the fact 
that the speed with which the armature coils cut the lines of force 
of the magnetic field is the chief factor determining the e.m.f. and, 
in consequence, the current output of the generator. This, in con¬ 
nection with the heating effect of the current due to the resistance 
of the conductor, limits the amperage that the latter will carry 
safely. Beyond this point the insulation will take fire and, with a 
further increase in the temperature due to excessive current, the 
conductors themselves will fuse. With the extreme variation in 
speed presented by the operation of the automobile engine, the 
necessity for regulating the output of the generator will be appar¬ 
ent. There are almost as many methods of regulation as there are 
systems in use. 

As explained in the section on Induction Sources of Ignition 
Current, Part II, the magneto is an electric generator that requires 
no current-controlling device, as the magnetic excitation of its fields 
is permanent. That is, barring gradual exhaustion through age, 
heat, and vibration, its magnetic field is constant, thus enabling it 
to generate a current at very low speeds; but the limitations of this 
type of field are such that electromagnetic fields are employed as 
in large direct-current generators. These fields depend for their 
excitation upon the current derived from the armature of the 
machine itself, and, as the amount developed by the latter increases 
in direct proportion to its speed, the fields become stronger as the 
speed increases and correspondingly more current is generated by 
the armature. As an automobile motor is driven at a great range 
of speeds, varying from 200 or 300 r.p.m. up to 2000 to 2500 r.p.m., 
or even higher, and the generator is usually geared in the ratio 
1:1§ so as to develop its rated output at the normal speed of the 
engine — its windings y^ould be quickly burned out unless some 
provision were made to control its output. 

Constant=Current Generator. Generators of the so-called con¬ 
stant-current type are frequently regulated by the winding alone. 
They are usually compound-wound, the series coil being so con¬ 
nected as to oppose the shunt. Assuming the coils to be in equally 
advantageous positions on the core, the limiting current then is one 


27G 


ELECTRICAL EQUIPMENT 


which gives the same number of ampere turns to the series coil as 
to the shunt field. Thus, assuming 500 shunt turns in the winding 
and a shunt current of one ampere, there are 500 ampere turns in 
the shunt winding. If there are 25 turns in the series winding, the 
limiting current will be 20 amperes, 500 being the product of 20 by 
25. With this winding 20 amperes will be the absolute limit of the 
current regardless of speed. As a matter of fact, it will be consid¬ 
erably lower than this in practice, owing to the armature reaction 
or counter e.m.f. generated. 

Slipping-Clutch Type, As in every case speed is the direct 
cause of a rise in the voltage or increase in the current output, one 
of the methods available for regulating generators is that of mechan¬ 
ically governing the speed at which the generator runs. In the Gray 



Fig. 14G. Section of Gray and Davis Lighting Dynamo (Early Model, Now Obsolete) 


and Davis, which is probably the most important representative of 
this type, a slipping clutch is used for this purpose. A centrifugal 
governor is employed, as shown in the sectional view. Fig. 14(). 
The drive is through a two-plate friction clutch at the left, the 
plates of this clutch being normally held in engagement by a spring. 
The tension of this spring is controlled by the centrifugal governor 
to which it is attached at the right-hand end, and it may be adjusted 
to compensate for wear by means of the threaded shaft and nut. 
This clutch is set to slip at a certain torque and, as soon as the 
current value corresponding to this torque is attained, the clutch 
lets go, and the current cannot exceed this limit. Accordingly, one 
plate of the clutch (the driving side) runs faster than the driven side 
in proportion to the difference in the speed of the gasoline engine 

















































































































































































































ELECTRICAL EQUIPMENT 


277 


and that at which the generator is designed to run, the torque on 
both sides of the clutch remaining the same regardless of this differ¬ 
ence. Ventilation is provided to carry off the heat produced by the 
slipping clutch, the opening and the arrows shown in the illustration 
indicating the direction in which air is drawn into and expelled from 



Fig. 147. Delco Third-Bru.sh Method of Regulation 


the housing. The generator is of the compound-wound type, and is 
known as a constant-speed constant-current dynamo. Regulation 
in this case is by purely mechanical means. 

Inherently Controlled Generator. Westing house Type. Atypi¬ 
cal example of inherent regulation is represented by the Westinghouse' 
















































278 


ELECTRICAL EQUIPMENT 


generator. (See Fig. 116, Part III.) When the generator is connected 
to the battery by the automatic cut-out, the current rises rapidly with 
the speed until a moderate value is attained. Current in excess of this 
value passes through a compound series winding, the polarity of 
which is opposite to that of the shunt winding of the fields. Conse¬ 
quently it acts to oppose the excitation set up in the field magnets 
by the latter above a certain point. This is known as a ^Tucking 
coil” and, while it permits the value of the current generated to 
increase slightly over the predetermined limit with a further increase 
in speed, it does not allow it to reach an excessive amount at any 
speed at which the car can be run. However, current for the lights 
does not pass through this reversed compound field winding and, 
when the lights are turned on, the output of the generator increases 
automatically to supply them. With the usiml lamp equipment, 
this increase in generator capacity is sufficient to operate the lamps 
without any demand on the battery at ordinary running speeds. 
At low speeds the battery supplies a certain proportion of the light¬ 
ing current, and when the engine is not running the battery takes 
care of the entire demand. When running at night, all current in 
excess of that required by the lights is utilized to charge the battery, 
which is thus said to ‘Toat” on the line. During the daytime, the 
entire output of the generator is absorbed in charging the battery. 

Delco Third-brush Excitation. Another form of inherent regula¬ 
tion consists of the use of a special brush for taking the current from 
the armature for the purpose of exciting the field. An instance of 
this is found in the Delco two-unit system as built for the Oak¬ 
land cars (1916 models). As the generator is a bipolar type, there 
are only two brushes for leading the current from the armature to 
the external circuit, so that the special regulating brush employed, as 
illustrated in Fig. 147, is commonly referred to as a “third brush”. 
This applies only to this particular type, however, for if the generator 
were a multipolar type having four brushes, the regulating brush would 
then be a fifth brush. The Delco generator is shunt wound but 
differs from the standard machine of that type in that the shunt 
winding is connected to the third brush which bears on the commu¬ 
tator between the other brushes. This method has the advantage 
of providing a strong shunt field at low speeds so that the generator 
commences charging while the car is still traveling at a very moder- 


ELECTRICAL EQUIPMENT 


270 


ate pace. As the speed increases the voltage applied to the shunt 
field is decreased, although the total voltage between the main 
brushes may have increased. This weakens the field and prevents 
the output of the generator from increasing with the increased 
speed. At the higher speeds it acts somewhat similarly to the 
bucking coil previously described, in that it still further weakens the 
field and causes the generator output to decrease. 

Bosch-Rushmore Type, In the Bosch-Rushmore generator, 
inherent regulation is obtained with a bucking-coil winding used in 
conjunction with a so-called “ballast” coil, which automatically cuts 
the bucking coil in or out of the circuit according to its resistance. 
Fig. 148. Advantage is taken of the fact 
that the electrical resistance of iron increases 
enormously after its temperature rises beyond 
a certain point. This ballast coil accordingly 
consists of a few turns of fine iron wire on a 
fluted porcelain rod. The bucking coil, the 
effect of which is to reduce the field excita¬ 
tion of the dynamo, is connected as a shunt 
across the iron ballast coil, as shown in Fig. 

148. Its resistance is considerably greater 
than that of the ballast coil when the latter 
is cold or only warm, so that at low engine 
speeds practically all of the current generated 
passes directly to the battery and lamps and 
the generator acts as a single-shunt dynamo. 

How^ever, the resistance of the iron wire in¬ 
creases at a constant rate up to about 10 amperes, after which it 
mounts very suddenly, preventing the passage of any excess current, 
which, accordingly, must go through the bucking coil. Thus the latter 
only comes into action at high speeds, so that the output of the 
dynamo may be adjusted to any value within its capacity simply 
by employing an iron wire of suitable diameter in the ballast coil. 

Independent Controllers. The Ward-Leonard controller (con¬ 
stant-current), Fig. 149, is typical of the external or independent 
controlling devices. In principle, this is the same as the Splitdorf 
and many others, the chief distinctions between the types usually 
being found in their construction. Referring to Fig. 149, the coil F, 



Fig. 148. Connections Bosch- 
Rushmore Generator 





























280 


ELECTRICAL EQUIPMENT 


on the magnet core G, carries the armature current, and when the 
latter exceeds a certain value—the standard being generally about 
10 amperes—the core becomes sufficiently magnetized to attract the 
finger II. This separates the contacts EE', and the resistance M 
is inserted in the field circuit and weakens it. The current then 
decreases, but when it drops to about 9 amperes, the pull of the 
magnet is not sufficient to overcome the tension of the spring J, 
and the contacts EE' come together again. In actual operation, 
the finger II is kept vibrating at a rapid rate. As a result, the 
dynamo cannot charge the battery at a rate in excess of 10 amperes, 
regardless of the speed. At all car speeds above a predetermined 

limit, usually 15 miles per 
hour in practice, the dynamo 
generates a substantially con¬ 
stant current. The regulat¬ 
ing device shown at the left 
of the figure is the automatic 
cut-out to break the circuit 
between the battery and the 
dynamo when the speed of 
the latter falls below a point at 
which it is no longer capable 
of producing the necessary 
voltage for charging. This 
is referred to later. 

All external regulators 
are not of the constant- 
current type, however, as some limit the voltage. 

Constant=Potential Generators. There is probably a greater 
variation in the methods employed to control this type than in the 
constant-current type. This difference is in the method rather than 
the principle employed, as the majority of such regulating devices 
act to control the potential by automatically inserting extra resist¬ 
ance in the field circuit or in series with the armature. Quite a 
number of generators of this type are fitted with a vibrating contact 
operated by a magnet in much the same manner as a vibrating 
ignition coil is actuated. The device is either built as a separate 
unit or is incorporated as in the Splitdorf earlier models. 



Fig. 149. Ward-Leonard Current Controller 
and Automatic Cut-Out 















ELECTRICAL EQUIPMENT 


281 


“Built-In” Regulator Type. In the Splitdorf generator, where 
the armature is supported by the usual ball bearings, the field poles 
have extensions which carry windings for the purpose of aiding in the 
regulation. Extending across these polar projections is a “keeper” 
(an unwound armature) held by a spring, and in connection with 
this keeper is a second spring for adjusting the tension of the first 
spring. The circuit of the battery is closed by the keeper being 
drawn toward the pole tips under the influence of their magnetism 
when the machine is running. The coils around these polar exten¬ 
sions are wired in series with the armature of the generator. When 
the current in the armature reaches a certain predetermined value, 



Fig. 150. Section of Splitdorf Generator Showing Controller 


the keeper is drawn all the way down and an auxiliary contact is 
opened which cuts a resistance into the shunt winding of the fields, 
and thus reduces the magnetic flux due to their action. This, 
together with the differential action of the series coils on the polar 
extensions, reduces the magnetic flux through the armature to such 
a value that the current to the battery does not increase beyond a 
certain value, no matter how fast the armature is turned. A sec¬ 
tional view of the machine illustrating the details mentioned is 
shown by Fig. 150. As the speed diminishes the reverse operation 
of the controller takes place. This generator is driven at twice the 
crankshaft speed of the motor, and when installed on a car with 
34-inch wheels and geared at 3.7 to 1 on direct drive, begins to 
















































































































2S2 


ELECTRICAL EQUIPMENT 




charge the battery at 7 miles per hour. The high-speed control 
acts when the car is running between 35 and 40 miles per hour. 

External Regulator Type, The Adlake generator is of the con¬ 
stant-potential type governed by an external regulating device, the 
details of which are shown in Fig. 151. While termed a “regulator”, 

it also incorporates the 
automatic battery cut¬ 
out and the fuses on the 
same base. This device 
has been in use on Pull¬ 
man railroad cars for a 
number of years, the dy¬ 
namo in that case being 
driven from one of the 
axles of the car. The prin¬ 
ciple is that of inserting 
added resistance in the 
field circuit of the dyna¬ 
mo as its output increases 
in order to maintain the 
voltage practically con¬ 
stant. Its operation is 
made clear by reference 
to the diagram, Fig. 152. 
G is a solenoid or hollow 
electromagnet, in the 
opening of which the 
plunger K may move 
vertically. The weight 
of K is counterbalanced by N, a small piston moving in the cyl¬ 
inder 0, small shot being put in this piston until both are in 
equilibrium. They are connected by a chain passing over M. An 
arm F, attached to M, carries a movable contact designed to make 
connection with the various contacts of the rheostat C, thus put¬ 
ting in circuit a greater or less number of the German-silver-wire 
resistance coils composing it. These coils are connected in series 
with the field of the dynamo, which is a plain shunt-wound 
machine. 


Fig. 161. Adlake “Regulator” 



















ELECTRICAL EQUIPMENT 


28 ;i 

In explanation of the wiring diagram for the Adlake regulator, 
Fig. 152, start at terminal A of the generator; the current flows to Ai 
on the regulator and thence to the fuse block a. It is here the 
shunt-field circuit begins. The field current flows from a through b 
to the rheostat terminal c and through a number of the sections 
of the latter, depending upon the position of the arm F, through 
this arm and back through d to the fuse block e, thence through 



the fuse to terminal Ci and from there to the terminal C of the gener¬ 
ator, thence through the two shunt-field coils and back to the negative 
terminal B of the generator. From B the current flows through the ^ 
generator armature back to A, thus completing the circuit. There 
being only one field winding, the current always takes the same path, 
(‘xcept that it has to flow through more or less of the resistance 
sections of the rheostat, of which there are fifteen. The path of the 
main or charging current is from the fuse block a to the connector 
















































































































































































284 


ELECTRICAL EQUIPMENT 


/, and through g into the solenoid coil G. It leaves this coil through 
h and flows to the contact block which connects by the wire j with 
the stationary contact screw H of the automatic battery switch. 
When the latter is closed for charging, the current flows across to the 
movable contact point I of the switch, and thence through the two 
lower or series coils of the automatic switch to the connector K. 
From this it flows to the terminal B of the regulator, which is directly 
connected with the positive terminal of the battery, and the current, 
after flowing through the battery, returns to the negative terminal 
B of the generator through connections clearly indicated. 

There are a number of variations in the methods of regulation 
employed, as well as some that are not given in the foregoing resume. 
These are explained in detail in connection with the descriptions of 
the different systems. 


PROTECTIVE DEVICES 

Various Forms. When fully charged, the storage battery holds 
in chemical form the equivalent of two or more horsepower, i.e., 
40 to 160 amperes at 6, 12, or 24 volts, according to the system 
employed and the capacity of the battery furnished. An accidental 
ground or short circuit in the wiring system would release all of this 
energy in a flash to the great detriment of the battery itself as well 
as to any of the apparatus or parts of the car that happened to be 
included in its path or circuit. To guard against damage from such 
a cause, various forms of protective devices are employed, and the 
different systems vary as much in this respect as they do in others. 
In some instances, a circuit breaker is depended upon to take care 
of all the circuits. In others, further protection is afforded by the 
employment of fuses, as well as a circuit breaker. • Fuses very 
generally are employed to protect the lighting circuits as well as 
some of the other circuits. 

Automatic Battery Cut=Out. It will be evident that, if the 
storage battery were at all times in direct connection with the 
generator, it would immediately discharge through the latter as soon 
as the driving speed fell to a point where the dynamo was no longer 
producing sufficient voltage to charge the battery. If the generator 
were free to run instead of being positively connected to the engine, 
it would become “motorized” and operate as an electric motor on 


ELECTRICAL EQUIPMENT 


285 


the battery current. As it is so connected, the battery current 
would simply burn out its windings, owing to the low resistance of 
the latter at low speeds. Consequently it is necessary to insert an 
automatic switch in the circuit in order to connect the battery with 
the generator when the speed of the latter reaches a certain point, 
and to disconnect it as soon as it falls below that value. Such 
switches are termed automatic cut-outs or ‘h'everse-current relays.” 
In single-unit systems, such as the Dyneto, no battery cut-out is 
employed. A single hand-operated switch controls both the ignition 
and the generator-battery circuits, so that this switch is left closed as 
long as the engine is running. Should the engine stall, the battery 
(‘urrent automatically ‘'motorizes” the generator and re-starts the 



Fig. 153. Remy Reverse-Current Relay 


engine. With such systems the engine must not idle slowly and 
the starting switch must not be left closed after the engine has stopped. 

Ward-Leonard Type. The Ward-Leonard, Fig. 149, is typical 
in that it clearly illustrates the principles upon which most of these 
devices are based, though their construction varies widely, as will be 
noted by Fig. 153. The switch mechanism is shown at the left 
of Fig. 149. In this device A is the coil, B the magnet core, C 
the movable arm, and DD' the contacts. The dynamo generates 
sufficient voltage at a car speed of approximately 7 miles per hour to 
attract C and hold it in position, closing the battery circuit through 
DD' and charging at any speed above starting speed. 

Adlake Type. In Fig. 151, the automatic cut-out switch is seen 
at the lower right-hand corner of the panel. This differs from the 
usual types in that it has two shunt and two series electromagnets. 







28G 


ELECTRICAL EQUIPMENT 


The closing of the switch is effected by the two upper or shunt coils. 
The current for these coils follows the path of the main charging 
current as far as the stationary contact screw II of the switch, from 
which a connection leads to the fine windings of the shunt coils; 
after passing through these coils, it flows through the wire I to the 
connector m, which is connected to the terminal Bi. Consequently, 
as soon as the generator begins to pick up, current flows through 
the two upper or shunt coils of the switch, and when the magnetism 
due to this current becomes strong enough the switch closes. Cur¬ 
rent then flows into the battery for charging, first passing through 
the two lower or series coils, which greatly increase the pressure at 
the contact points as long as the charging current is flowing, and 
insuring a positive interruption of the current when the generator 
voltage drops below that of the battery. A powerful actuating 
force is thus obtained with very small magnets. 

Circuit Breaker. Circuit breaker, as employed in this connec¬ 
tion, must not be confused with ^‘battery cut-out”. The cut-out is 
literally a circuit breaker and is referred to as such by some manu¬ 
facturers in their instructions, but in electric terminology, as 
employed in everyday use, the circuit breaker and the cut-out are 
entirely different things. A circuit breaker is designed to operate 
only when a current considerably in excess of that for which its cir¬ 
cuit is intended passes through it. Whether a protective device is 
a cut-out or a circuit breaker may be determined by the circuit in 
which it is placed. The cut-out is never employed in any other 
circuit than that of the generator and battery. A detailed explana¬ 
tion of the circuit breaker is given in connection with the Delco 
system. 

STANDARDIZATION 

Voltage Standards. Weight reduction is a problem of the 
greatest importance on the automobile and as energy in the form of 
a lead-plate storage battery is very heavy, the size of the latter is 
very closely limited. Power, however, depends not so much upon 
the amount of energy available as it does upon the pressure at which 
it can be applied. Thus, by doubling the voltage of a storage bat¬ 
tery, the capacity needed can be reduced correspondingly. Where 
only three cells are employed, they must be very much larger than 
when six are used, and the cells of the latter must be correspond- 


ELECTRICAL EQUIPMENT 


287 


ingly larger than those of a 9-cell or a 12-cell battery. While 
there are a few adherents of the higher voltage battery repre¬ 
sented by the systems in use today, the majority favor the 6-volt 
standard. 

Variation by Manufacturers. A final difference to be noted is 
that systems of totally different characteristics are turned out by 
the same manufacturer. Automobile motors are still a long way 
from reaching a degree of standardization that permits them to be 
classified according to horsepower, dimensions, number of cylin¬ 
ders, or any other easily applied standard so far as their require¬ 
ments from an electrical point of view are concerned. The manu¬ 
facturer of electrical apparatus accordingly designs a starting and 
lighting system to meet the requirements of a certain motor and it 
will give the most efficient service only when applied to that par¬ 
ticular motor. This accounts for the major part of the great vari¬ 
ation in electrical systems that exists and particularly for the differ¬ 
ence between the equipment of the successive models of the same 
make of automobile. For that reason, it must never be concluded 
that a Delco, a Gray & Davis, a Bijur, a Wagner, or any other 
starting and lighting system is always the same on whatever car it 
may be found. Automobile manufacturers alter the characteristics of 
their motors from year to year, and the manufacturer of electrical 
apparatus not only keeps pace with this by redesigning his system 
to correspond but also introduces various improvements suggested 
by experience and the development of the art. In consequence, it 
would be manifestly impossible to attempt to outline in detail the 
features of every starting and lighting system to be found on all 
the cars now running, thousands of which are three to five years 
old. The following analysis accordingly covers only those of more 
recent manufacture, but by a study of these it will be easy to become 
familiar with the general characteristics of all, and to note at a glance 
where improvements have been made from year to year. 

STARTING MOTORS 

Speaking broadly, there are three classes of starting devices 
worthy of mention, viz, the mechanical or spring-actuated devices; 
the compressed fluid devices; and the electrical starters. While still 
employed to some extent abroad, compressed air and similar devices 


288 


ELECTRICAL EQUIPMENT 


are now only of historical interest here as they have been displaced 
almost entirely by the electric starter. 

Modern Electric Starting System Anticipated Sixteen Years. 
Although it has only come into general use within the last few years, 
the possibilities of the electric starter on the automobile were fore¬ 
seen at an early day. Those to whom it has appeared as a novel 
development of very recent adoption will doubtless be surprised to 
learn that a car embodying many of the features of present-day 
electrical systems was built in 1896. Indeed, the following descrip¬ 
tion of it might well apply to the present U.S.L. system, which 
employs the flywheel type of dynamotor. The machine in question 
was a Diehl specially wound Gramme-ring type designed to operate 
at 12 volts. The armature, which weighed 111 pounds, served as 
the flywheel of a two-cylinder horizontal opposed 6- by 7-inch 
motor. The system was described as follows: 

“The flywheel is constructed as a dynamo, which by rotary 
motion charges a storage battery carried in the vehicle. At the time 
of starting the carriage, the motorman turns a switch which dis¬ 
charges the storage battery through the dynamo, converting it for 
a few seconds into a motor, which, being upon the main crankshaft, 
gives rotation and does away with the necessity of starting the fly¬ 
wheel by hand. After the motor gives the crankshaft a few turns, 
the cylinders take up their work and the battery is disconnected 
from the dynamo, which then acts as a flywheel. 

“The flywheel dynamo furnishes the current for the induction 
coil of the sparking mechanism as well as for the electric lamps at 
night, thus doing away with the necessity of going to a charging 
station. Attached to the crankshaft is a device for changing the 
point of ignition of the spark in the combustion chamber, perfectly 
controlling the point of ignition, acting as a ‘lead’ and allowing the 
motors to be operated at a variable speed, according to the work 
done.” 

From this it will be seen that as early as the spring of 1896, the 
present complete electrical equipment of the automobile, including 
ignition with automatic spark advance, electric lighting and starting, 
was fully worked out and applied to an actual machine. It was 
not until sixteen years later that what had been anticipated at such 
an early day in the history of the automobile became accepted 


ELECTRICAL EQUIPMENT 


289 


practice in all the essential points mentioned. In addition, the 
machine in question was provided with a magnetic clutch which 
automatically connected and disconnected the engine every time 
the gear-shifting lever was moved, thus anticipating the present-day 
electromagnetically operated gearbox. 

Requirements in Design. The conditions in applying an 
electric starting motor to the gasoline engine bear no relation what¬ 
ever to those of the lighting dynamo, so that the problem is not, as 
might be supposed, merely a question of reversing the functions of a 
single unit of the same characteristics. Practically the only require¬ 
ments of the dynamo that differ from standard practice in other 
fields are that it shall commence to generate at a comparatively low 
(car) speed and that its output shall not exceed a safe limit no matter 
how high the speed at which it is turned over. The problem of the 
starting motor, on the other hand, involves conditions which have 
not had to be met in the application of electric motors to other 
forms of service. For example, a very high torque must be devel¬ 
oped to overcome the inertia of the load, and the latter takes 
the form of intermittent rather than of steady resistance to the 
driving effort, owing to the alternate compression and expan¬ 
sion in the motor cylinders. The trolley car might be cited as 
a 'parallel to the hea\’y starting torque required, but the intermit¬ 
tent load, as well as the highly important limitations of weight, 
restricted current supply, voltage, and space considerations, are 
entirely lacking. 

In the last analysis, the electric starter is nothing more nor less 
than a storage-battery starter, since most of its limitations are 
centered in that most important essential. The matters of driving 
mechanism, starting speed, and other equally important details can 
all be based on what is either accepted practice of long standing in 
other fields, or on the knowledge of starting requirements gained in 
the years of experience in applying manual effort to that end, but the 
storage battery will always constitute the chief limiting factor. 
This should be borne in mind in considering the forms that various 
solutions of the problem have taken, and, above all, it must be 
given first consideration in the successful maintenance of any elec¬ 
tric starting system, as the majority of troubles met with have their 
origin in the neglect of the battery. 


290 


ELECTRICAL EQUIPMENT 


Wide Variation in Starting Speeds. In view of the long experi¬ 
ence in hand-cranking the motor, it would seem that a definite basis 
for the starting speed would be an easy thing to establish, but this 
has not been the case. If “motor” briefly summed up in one word 
all of the varying characteristics to be found in the great variety of 
engine designs to which starters must be applied, this might have 
been easier of accomplishment. What suffices to start one make is, 
however, frequently found to be totally inadequate for others of 
apparently identical characteristics, so that in the different makes of 
starters this essential is found to range all the way from 25 r.p.m. 
to 200 r.p.m. or over. The necessary speed is largely influenced by 
the carburet ion, as with the stand-by battery ignition almost univer¬ 
sally provided, dependence need not be placed on the magneto to 
start; but to draw a mixture from^the carbureter of a cold engine 
calls for speeds in excess of the lower limit of the range given. The 
most severe service demanded of the starter and the time when it is 
most needed are coincident, i.e., in winter use, and the equipment 
must naturally be designed to meet successfully the most unfavor¬ 
able conditions. Even with starting speeds of 100 r.p.m. or over, 
it has been found impossible to start some motors without resort to 
priming. Some idea of the great variation in the speeds adopted 
will be evident from the fact that the North East starter, as originally 
built, was designed to turn the IMarmon six-cylinder motor over at 
only 25 r.p.m.; the Hartford on a similar motor at 70 r.p.m.; the 
Westinghouse, 80 r.p.m.; Delco, 150 to 175, and the LLS.L. at 200 or 
over. These speeds are not invariable by any means, as in every 
case the starting equipment is designed particularly for the motor 
to which it is to be applied, and will run at different speeds in accord¬ 
ance with the requirements of the engine on which it is installed. 

Practice Becoining Standardized. So far as practice may be said 
to have become standardized at the present writing, speeds of 80 to 
100 r.p.m. represent a close approach to the average. One of the 
reasons for making the speed so much higher than could be effected 
by hand-cranking is the slowing down of the motor as the pistons 
reach the maximum compression point in the cylinders, while another 
is the necessity for drawing a charge of fuel from the carbureter 
under the most adverse conditions so that starting shall alwavs be 
accomplished without resort to priming. 


ELECTRICAL EQUIPMENT 


291 


Voltage. When an engine has been standing idle for some time 
at a temperature well below the freezing ])oint, the lubrieating oil 
becomes extremely viscous and the current required for starting at 
a low voltage is very high. The 6-volt standard inherited from 
dry-cell-ignition days accordingly appeared to be entirely too low 
at the outset, and several systems employing 12- and 24-volt bat¬ 
teries were developed. The higher efficiency of the latter in start¬ 
ing is opposed by certain disadvantages inherent in this type of 
installation. Experience has shown, however, that with proper 
installation and maintenance the 6-volt system affords advan¬ 
tages which more than 
offset any increase of 
efficiency derived from 
the use of a higher 
voltage, and the majority 
of well-known starting 
systems are now designed 
to operate on a potential 
of 6 volts. 

Motor Windings and 

Poles. The necessity for 
developing a powerful 
torque at low speeds 
naturally calls for a 
series-wound motor, such 
as is employed in street- 
raihvay and electric- 
automobile service, and aU starting motors are of this type. Motors 
built to operate at such a low voltage being new to the electrical 
designer there is more variation in the form and size of starting motors 
than exists in power units running on current at commercial voltages. 

Standard Designs. Briefly stated, the electrical requirements 
demand a concentrated and correctly proportioned mass of iron 
and copper in the minimum space. The cross-sections, Fig. 154, 
show how these requirements have been met in various instances. 
As the motor is only required to operate for very short periods, both 
the conductors and insulation can be kept down in size as compared 
with a motor designed to run constantly under heavy load. 



Fig. \rA. Cross-Sections Typical Electric Starting Motor 
Courtesy The Automobile, New York City 




































































292 


ELECTRICAL EQUIPMENT 


Commercial Forms. The problem is to provide for a certain 
number of ampere turns around the poles and a magnetic circuit 
through the latter, as well as steel housing or frame of sufficient cross- 
section to carry the required degree of magnetization with the 



Fig. 155. Section of Bosch-Rushmore Starting Motor 

shortest magnetic circuit. Consequently, shallow windings with 
long flat pole pieces are more efficient than the reverse of this form, 

' particularly as air space in the magnetic field lessens its intensity 
and calls for a heavier winding to magnetize the extra weight of 
metal to the same degree. Hence, the type represented by R, 
Fig. 154, is the most efficient, in theory at least, of the four forms 
illustrated. 

Whether the windings be placed on two poles or on four poles is 
something that each designer decides according to his own prefer¬ 
ence in the matter. The Bosch-Rushmore starting motor. Fig. 155, 



Fig. 156. Westinghouse Starting Motor 


exemplifies type B referred to above, except that it is bipolar. Wind¬ 
ings and pole pieces of the same type are shown in the Westinghouse 
starting motor. Fig. 156, this being patterned after form D in 
Fig. 154, though it is of somewhat broader section. The auxiliary 























ELECTRICAL EQUIPMENT 


293 


unwound pole pieces at the sides do not show very clearly in the 
illustration; they are of substantially the same form, though con- 



Fig. 157. Bipolar Type Westinghouse Starting Motor 


TRANSMISSION AND 
REGULATION DEVICES 



siderably wider than those illustrated in the section in question. 
For a more restricted space a straight rectangular bipolar type is 
made, Fig. 157. From 
the standpoint of 
both electrical efficiency 
and space consider¬ 
ations, practice favors 
the cylindrical rather 
than the rectangular 
form. 


Installation, As the 

driving requirements of 
starting with such a 
small power unit as 

space and weight lim- Fig. ISS. Double-Reducing Gear Type Installation, 

. . - Wagner Starting Motor 

itations make necessary 

call for a high-speed motor and a high gear ratio to effect the neces¬ 
sary speed reduction, the mounting of the starting motor is totally 
















204 


ELECTRICAL EQUIPMENT 


different from that of the lighting dynamo. The eleetrie motor 
runs at 1800 to 3000 r.p.m. or over, according to its design, while, as 
already mentioned, the engine starting speeds usually average 80 to 
100 r.p.m. The great speed reduction required is effected in the 
majority of instances by utilizing the flywheel as the driven gear, a 
gear being bolted to it, as shown in Fig. 158, which illustrates the 
application of a Wagner starter to the IMoline-Knight 50 horsepower 
four-cylinder motor. Or the gear teeth may be cut directly in the 
periphery of the flywheel itself, as shown by the Delco single-unit 



Fig. 159. Mounting of Delco Single-Unit Sy.stem 

system mounted on a Cartercar four-cylinder engine, Fig. 159. In 
either case, this does not afford sufficient reduction in the speed, and 
an intermediate set of gears is necessary in installations such as 
those illustrated. This gearing may be mounted as an attachment 
to the engine or combined with the starting motor, as shown in Fig. 
160, showing a Ward-Leonard starting motor with enclosed gearing. 
In some instances, a planetary type of gear is employed, an example 
of which is found in one type of the Westinghouse starting motors. 
Fig. 161, the gearbox being incorporated in the motor housing and 

















ELECTRICAL EQUIPMENT 


295 




the pinion driving direct. In view of the large reduction available 
in a planetary gear, a starting motor of this type may be employed to 
drive through a camshaft or 
similar location. Planetary 
gears are also utilized on some 
of the single-unit systems, 
such as the Northeast, the 
gear ratio used being some¬ 
thing like 40 to 1 when the 
dynamotor is used for start¬ 
ing and 1 to IJ or 2 when 
running as a generator. Fig. 

162. Silent chains are made 
use of in some cases, but this is done more frequently where a start¬ 
ing and lighting system is applied to an old car rather than to one 

for which it has been es¬ 
pecially designed. Where 
the starting motor is of a 
comparatively low-speed 
type, the single reduc¬ 
tion between the motor 
pinion and the flywheel 
suffices. Fig. 163 shows 

Westinghouse Starting Motor with Planetary txt j j 1 j. a* 

Reduction Gear a Ward-Lcouard Starting 


Fig. 160. Reducing Gearing Attached to 
Ward-Leonard Starting Motor 


Fig. 161. 



Fig. 162. Mounting and Drive of Northeast Dynamotor 


























































29G 


ELECTRICAL EQUIPMENT 


motor designed for direct engagement with the flywheel gear. The 
purpose of the spring shown on the end of the shaft is to pull the 
pinion quickly out of engagement when the motor takes up its cycle, 
as explained in the following sections. 

Driving Connections. Except in the case of the single-unit type, 
which is in a permanent driving relation with the engine, it is neces¬ 
sary to provide some form of 
driving connection with the 
engine in order that the elec¬ 
tric motor may turn it over 
to start, and release it the 
moment the engine fires. The 
method of accomplishing this 
is made clear by a brief study 
of Fig. 164, which shows an 
Overland four-cylinder motor 
with an Auto-Lite two-unit system, the starting motor only being 
shown. In this installation the control button or starting pedal 
serves both to connect the motor with the battery and to engage 
the driving pinion with the toothed ring of the flywheel. Typical 
examples of this form of control are found on the Locomobile and 

Peerless, which differ 
only slightly in detail in 
their methods of install¬ 
ing the Gray and Davis 
starting motor. The 
switch is usually located 
directly beneath the 
footboards just back of 
the dash. Depressing 
the pedal part way makes 
preliminary contact 
through a resistance, 
turning the electric motor over very slowly, and at the same 
time draws the starter pinion toward the flywheel gear, its slow turn¬ 
ing insuring easy engagement. As the pedal is depressed further, it 
breaks the first contact and closes the main switch, sending the entire 
battery current through the starting motor and turning the engine 




Fig. 163. Ward-Leonard Starting Motor for 
Direct Engagement 





ELECTRICAL EQUIPMENT 


297 


over rapidly. Releasing the pedal automatically opens the switch 
contacts and disengages the starting motor from the flywheel. It 
is also frequently made in the form of a pedal and placed on the slope 
of the footboards under the cowl of the dash, the location in any case 
being dictated by the necessity of keeping it out of the way of the 
other controls of the car. 

Automatic Engagement. Auto-Lite Type. Fig. 165 illustrates an 
improvement on the foregoing method, which eliminates the neces¬ 
sity of mechanically engaging the starting pinion with the flywheel. 
This is an Auto-Lite generator on an Overland six motor. In starting, 
the depression of the pedal cuts in a resistance in the same manner, 
at first, as it would not 
only be unsafe to send 
the full strength of the 
current through the 
motor before it picked up 
the load, but it would also 
be impossible to mesh the 
pinion at full speed. In 
this starting motor, the 
pinion is cut on a sleeve 
surrounding the arma¬ 
ture shaft of the motor, 
and this sleeve is nor¬ 
mally held out of engage¬ 
ment by the spring shown. 

On the armature shaft a thread of coarse pitch is cut which engages the 
inner surface of the sleeve. When the starting motor begins to turn 
slowly as the current from the battery enters it through the resistance, 
centrifugal force moves the sleeve with the pinion along it toward the 
right until the latter meshes with the flywheel gear. As soon as the 
current is cut off, the spring draws the pinion out of engagement. 
This is known as theBendix driveandis rapidly becoming standardized. 

Bosch-Rushmore Type. Another form of automatic engage¬ 
ment, which is electrically operated in this instance, is that of the 
Bosch-Rushmore starter. By referring back to Fig. 155, which 
shows a section of this starting motor, it will be noted that there is a 
heavy spring on the left-hand end of the armature shaft and that 








298 


ELECTPvKWL EQEIPIMENT 


the armature itself is normally held out of its usual rimiiiug position 
by this S})riug. Iii other words, it is not eeiitered in the armature 
tunnel but is two inches or more to the right of the center of the 
magnetic field. This is just sufficient to keep the pinion out of 
mesh when the motor is installed, as shown in Fig. 166. The first 
contact of the starting switch sends sufficient current for the field 
poles to exert enough magnetic drag on the armature to draw it 
back into its normal centered position, at the same time turning it 
over slowly, so that engagement is quickly effected automaticalh'. 
The moment the current is shut off, the spring pushes the armature 
back and disengages the pinion. Exceptions to the practice reflected 
by the foregoing examples are to be found on cars like the Reo, in 



Fig. 166. Mounting of Bosch-Rushmorc Starting Engine 


which the Remy starting motor is mounted on the transmission hous¬ 
ing and drives to one of its shafts through a worm and worm wheel. 
The latter lowers the speed sufficiently through a single reduction, and 
the revolution of the armature in starting picks up a clutch which 
automatically releases as soon as the engine starts. 

Clutches. Necessity for Disengaging Device. To prevent the 
gasoline engine from driving the starting motor when the former 
takes up its cycle, some form of over-running clutch must be provided 
unless the starter is geared directly to the crankshaft or has a mechani¬ 
cal disengaging device, such as the Bendix or electrical, as the Bosch- 
Rushmore and Westinghouse. To take care of the speed reduction, 
assume that this gear ratio is 30 to 1 and that the throttle is half open 












ELECTRICAL EQUIPMENT 


299 


when the engine is being cranked. As soon as the explosions begin to 
take place, the engine will shortly speed up to about 500 r.p.m. 
Before the gasoline engine is started, however, the electric motor will be 
running pretty near its maximum rate, say 3000 r.p.m. An electric 
motor of this type will run as high as 5000 r.p.m. safely, but speeds in 
excess of this are liable to damage it. If the throttle of the engine 
should happen to be three-quarters of the way open when started and 
it should speed up to 1000 r.p.m. before the starting motor was disen¬ 
gaged, the armature shaft of the latter would attain a speed of 15,000 
r.p.m., which is far beyond the safety limit. This makes it necessary 
to provide some device which, while permitting the starting motor 
to drive the engine, will 
])revent the latter from 
driving the starting 
motor as soon as the 
former takes up its regu¬ 
lar cvcle. 

A number of differ¬ 
ent devices are employed 
for this purpose, such as 
the jaw clutch similar to 
that employed on all 
handcranks, roller clutch, 
friction clutch, pawl and 
ratchet, inertia clutch, 
worm and worm wheel, 
and others. A description 
of one or two types will suffice to make clear the principle on which 
most of the mechanical devices are based. The roller clutch and.the 
over-running jaw clutch are most frequently used. With starters of 
the design of the U.S.L., shown on a Sheffield-Simplex (British) six- 
cylinder motor in Fig. 167, it is obviously unnecessary to provide 
any form of flexible coupling, as the armature is mounted directly on 
the crankshaft and consequently cannot exceed the speed of the latter. 

Where the crankshaft is driven direct through a train of gears 
or a combination of gears and a silent chain, the clutch is usually 
placed between the last gear of the train and the crankshaft. None 
of the gears is then in operation exce])t when starting. On the 





300 


ELECTRICAL EQUIPMENT 




flywheel-gear type of installation used in connection with a second- 
gear reduction by means of a countershaft, Fig. 158, the clutch 
is placed on the countershaft. Otherwise, it is mounted on the arma¬ 
ture shaft. In the case of a worm 
and worm-wheel drive, it is incor¬ 
porated in the worm wheel. 

Roller Type. The roller type 
is the most commonly used and, 
as the various forms in which it is 
made differ but little, a descrip¬ 
tion of one will suffice to make 
clear the principle employed. It 
consists of an inner driving mem¬ 
ber and an outer driven member, 
connected by a number of rollers 
when the driving member is 
rotated in one direction and dis- 

Fig. 168. North East DoubloHoller Over- pptprl aazVipti it iQ in 

Running Clutch {Horseless Age) COnneCICa WHeil IL lb rOtdXeU 111 

the opposite direction, i.e., when 
the driven member tends to run faster than the driver. Fig. 168 
shows the double-roller over-running clutch employed on the North 

East dynamotor. A double clutch 
is employed in this case to permit 
the dvnamotor to be driven at 
one speed when operating as a 
dvnamo and at another when 
starting the engine. Fig. 169, 
which shows the Leece-Neville 
starter on a Haynes six-cylinder 
motor, is an example of the use- 
of a roller clutch and chain in 
place of the gear and pinion con¬ 
nection previously described. 

Back=Kick Releases. As the 
starting motor has more than 
sufficient power to overcome a back-kick or premature explosion 
(with the spark-timing lever too far advanced) of the engine, and is 
only slowed down by it, only a few instances of the employment of 


Fig. 109. 


Leece-Neville Starter Installation, 
Haynes Motor 









ELECTRICAL EQUIPMENT 


301 


Slorling 



BoHert£ 


f’lywheel 


H'hli 


Starling 
Pedal 


mM-s 


'^Switch \ 

Return Spring 



a back-kick release are found in practice. One of these on the 
Northeast starter is in the form of a friction clutch held in contact 
by springs, dhis clutch will slip under such circumstances. A fric¬ 
tion disc clamped between 

i 11. . . Battery^ 

two steel discs, similar to a '■ 

shock absorber, is employed 
on the Hartford starter, this 
being required because of the 
irreversible worm and worm- 
wheel drive used, as the teeth 
of the latter would be injured 
in case the engine ‘‘back- 
kicked”. Another device em¬ 
ploys a brake band on the 
starting gears so designed 
that it holds in one direction 
only. 

Switches. Two types of 
switches are employed in 
connection with starting and 
lighting systems—those de¬ 
signed to control the lighting 
circuits to the various lamps, 
and those employed to con¬ 
nect the battery with the 
starting motor. As the first Battery 

type seldom carries more 
than 5 amperes at 6 volts ( 
and proportionately less at 
higher voltage, it does not 
differ from the standard 
forms of switches employed 
for house lighting, except 
that it is made much smaller 

„ „ „ i.; „ ^ flVTA _JC. £ T^l 1 

Connections of Motor and Switch for Flywheel 
Size TThe starting SV^ltch Drive with Double~Cear Reduction (^iVcst'ifiQhouss) 

on the other hand, has to carry currents ranging from 50 to 250 
amperes or more at voltages varying from 6 to 24, so that such a 
switch must be well built mechanically and have liberal contact 



Battery^ ^ 


[ 








Starting 
Pedah 



Flywheel 


Return Spring 


Storting 
Pedal, 



H Switch 

Return Spring 
Flywheel 











































































































































302 


ELECTRICAL EQUIPMENT 


areas. On account of the heavy currents handled by these switches 
there is a tendency to destructive arcing at the contact points unless 
provision is made to prevent it. 

Westinghouse Starting Switch. For starting use, two forms of 
switches are employed according to the method by which the motor 
starts the engine. Where the motor is connected directly to the bat¬ 
tery terminals by the switch, as in the case of single-unit systems such 


as the Delco, only a single set of contacts is necessary; but in case 
gears must be engaged before the starting motor can take the full 
battery current, two progressively operated sets of contacts are used. 
The first set completes the circuit through a heavy resistance to turn 
the starting motor over very slowly, and the second set cuts out this 
resistance, the driving gears then being engaged. The operation 
of a switch of this type is graphically illustrated by a series of sketches. 







Fig. 171. Details of Westinghouse Switch 


Fig. 170, showing a Westinghouse starter installation. In sketch A, 
both contacts are open, the return spring holding them apart. When 
the starting pedal is partly depressed, as in sketch B, the first set of 
contacts P come together and current from the battery passes to the 
starting motor through the resistance R. This connection continues 
through the spring fingers P and PI until the sliding member is almost 
in contact with the main-switch points Q, when it is broken and the 
circuit is directly closed with the battery by a butt contact. The 
operation only requires a fraction of the time necessary to describe it. 
The moment the foot is removed from the starting pedal, the return 
spring automatically breaks the circuit. The construction of this 
switch is shown in Fig. 171. Switches of this type are usually 
mounted directly under the footboards, a slight movement being 
sufficient to close the contacts. The starting plug may be removed by 








ELECTRICAL EQUIPMENT 


303 


the driver when leaving the car to prevent tampering, a pin across 
the tube making it impossible to insert a pencil or stick. The resist¬ 
ance mentioned is in the form of 
a ribbon and is incorporated in 
the switch. 

Miscellaneous Starting 
Sivitches. The type of switch 
used in connection with the Remy 
system is shown in Fig. 172. 

Both this and the Westinghouse 
switch described are known as 
butt-contact switches. The knife 
type of switch is also employed in 
several systems, Fig. 173 showing 
the Dean switch of this class. A 
somewhat unique form of contact 
is shown in the Gray and Davis 
switch. Fig. 174. There being no 
starting gears to mesh, it is only 
necessary to turn the current 
directly from the battery into the 
motor to start. P is the foot button of the starter, F the floorboard 
of the car, and 7' and M the terminals of the switch from which cables 
are led to one side of the battery and to one of the motor brushes, the 
others being grounded, as this is a single-wire system. Into the cast 



receptacle of the switch is fitted an insulating disc carrying the con¬ 
tacts C and 0 and also serving to insulate the terminals. These con¬ 
tacts are circular in form, and their free ends are turned away from 
each other so as to slip down over the knives R and S set in the insu- 





















































304 


ELECTRICAL EQUIPMENT 


lated disc. The contacts are pressed downward by P, which is 
returned by the spring G pressing against the spindle P. The termi¬ 
nals T and M are fastened to the semicircular knives R and S, respect¬ 
ively, so that bringing down the contacts C and 0 upon these knives 



Fig. 174. Gray and Davis Button Starting Switch 


completes the circuit from T to M. Numerous other forms of foot- 
operated switches are also employed, the Gray and Davis laminated 
contact switch. Fig. 175, for flywheel-gear installations, and the Ward- 
Leonard ‘‘harpoon” type. Fig. 176, being representative examples. 



Fig. 175. Gray and Davis Laminated Type of Starting Switch 
Courtesy of The Horseless Age 


Electrically Operated Switches. In this type a conventional 
push-button switch, either on the dash or mounted on the steering 
column, as shown in Figs. 177 and 178, which illustrate the Packard 
and Overland control, respectively, takes the place of the foot button. 
This push-button switch, however, only handles a shunt current of 
low value, which energizes a solenoid to close the contacts of the main 


























































ELECTRICAL EQUIPMENT 


305 


switch and also to engage the gears where this is necessary. The 
Westinghouse magnetically operated switch is explained in detail 
in connection with the description 
of that system. This form of 
control is employed on electric¬ 
railway trains and on electric 
automobiles. In addition to 
housing the push-button switch 
of the starting system, the two 
steering column control units 
mentioned also incorporate all the 
switches necessary to control the 
entire electrical equipment of the 
car, as will be noted by the indi¬ 
cations alongside the various but¬ 
tons on the Overland controller. 

A complete wiring diagram of 
the Packard six-cylinder con¬ 
troller is shown in Fig. 144. 

Where a higher potential 
than the usual 6-volt standard is 
employed, the switch has another 
function, which is that of chang¬ 
ing the battery connections from the multiple arrangement used for 
lighting to the series connection necessary to send the full voltage and 

current of the battery 
through the starting 
motor. This is the case 
with the U.S.L. system, 
which is made in either 
12—6-volt or 24—12-volt 
forms. 

Fuses. Standard 
practice favors the em¬ 
ployment of fuses on 
all the lighting circuits 
to protect the battery- 
in (*ase of short-circuits 



1 

ri 

fM 

/ W/m 

i 1 


—\ 

If 

'I. 

9il 

i« 

l^fi 

iliill 

um 

I11?) 

Pi 

|![ # JH! Lly 

:'i| 

!'il ' 

jjlj i|l| 

S 4 

1 jl 

i )«P 

^ sl 

* 

c 

it 

r’ 'll 

In 

'‘(’ft ';: 

111 i l|liil'!liill!|l 

tik^, A 1 

1 

is: 

yi 


fl 

\ 


Pig. ]7(). Ward-Leonard “ Plarpoon” 
Starting Switch 







































































































































































































































































3()G 


ELECTRICAL EQUIPMENT 




Fig. 178. Overland Electrical Control 


in any of the wiring. They were originally considered unnecessary 
on two-wire systems, but have since been adopted on the latter as well 
as on the single-wire system. Such fuses are of the cartridge type 
of miniature size, as shown in Fig. 179, which represents a Westing- 

house fuse block, and do not 
produce a flash when they 
blow, which is a safety fea¬ 
ture of importance in the 
presence of gasoline. The 
appearance of a black spot 
on the label indicates that 
the fuse has burned out, or 
these fuses mav be had in 
glass tubes through which 
the fuse wire is visible. 

A double reading am¬ 
meter, mounted on the dash and illuminated at night by a hooded 
lamp, shows whether current is being sent into the battery or being 
taken out of it, the needle usually moving over a scale to the right 
of the neutral line for charging and to the left for discharging. Fig. 
180. This dash lamp is usually connected in series with the tail lamp, 

so that when it goes out it is an 
indication that the tail lamp is 
out as well. A voltmeter some¬ 
times is provided to indicate the 
condition of the battery. In the 
Bosch system, this is combined 
with the lighting switches, as 
shown in Fig. 181. 

In some systems, an indi¬ 
cator is employed instead of an 
ammeter, a movable target ap¬ 
pearing at a small opening in the 
instrument and simply reading 
“Off” and “On” or “Charge” and “Discharge”. Such an instrument 
need not be so accurate as an ammeter and is more durable. These 
indicators never came into general use, however, and will be found 


Fig. 179. Type of Fuse Employed on 
Lighting Circuits 


on comparatively few cars, usually models of two or three years ago. 








ELECTRICAL EQUIPMENT 


307 


Electric Horns. Tlie use of a storage battery which is of suffi¬ 
cient capacity for starting purposes and which is kept constantly 
charged by the lighting generator has made it possible to employ 
numerous auxiliary electrical devices. The electrical horn is the 


chief of these, and it has to a very large 
extent displaced warning devices of 
every other class. Two different types 
of electric horns are used, in both of 
which the sound is produced by the 
vibrations of a sheet-metal diaphragm 
several inches in diameter. The onlv 
difference between the two forms lies in 
the method of causing this diaphragm 
to vibrate, one employing a small elec¬ 
tric motor and the other a simple electric 
magnet. Fig. 182, which is a phantom view of the operating 
mechanism of a Klaxon horn, shows the first type. On the upper 
end of the armature shaft of the electric motor is fastened a 
toothed wheel which strikes the button in the center of the dia- 



Fig. 180. Gray and Davis 
Ammeter 




Fig. 181. Bosch Voltmeter 
and Switches 


Fig. 182. Phantom 
View Klaxon Horn 


phragm and sets it vibrating at the rate of several thousand 
times per minute, giving rise to the raucous squawk which has come 
to be identified with automobile warning signals. As shown in 
Fig. 183, which illustrates a section of the Apollo horn, this type is 
nothing more nor less than an ordinary buzzer on an enlarged scale. 
















KLECTl^lCAT. lOQUIPMENT 


308 

The armature of the electromagnet vibrates at high speed produc¬ 
ing a sound by taps on the rod attached to the diaphragm. 

Care of the Electric Horn. As the operation of the electric horn 
is based upon exactly the same principles as the essentials of the start¬ 
ing and lighting systems, the instructions given for the care and adjust¬ 
ment of the latter will apply to it as well. In the case of the motor- 
driven type of horn, the commutator and brushes of the motor will 
require attention from time to time. Failure to operate may be due 
to a broken connection at the horn or at the battery; ground in the 
circuit between it and the battery; brushes not bearing properly on 
the commutator; or an excess of oil and dirt on the latter. If the 
motor runs properly, but the horn produces either no sound or a very 
weak sound, the trouble will be due to the poor contact of the toothed 
wheel with the button on the diaphragm. This button is made 



Fig. 183. Mechanism of Apollo Electric Horn {Horseless Age) 


glass hard to obviate wear at that point, but, in time, replacement of 
either the button or the toothed wheel or of both may be necessary. 

The attention required by the vibrating type of horn, of which 
there are many thousands in use, is very similar to that described 
for the battery cut-out and the voltage regulator. The contact 
points will require cleaning, truing up, and adjustment at intervals, 
and the spring may also need occasional attention. Failure to 
operate may be caused by a loose connection or break in the circuit, 
or by a lack of adjustment which causes the contacts to be held 
apart so that no current can pass through the winding of the 
electromagnet. A weak sound from this horn will result either 
from insufficient current or from lack of adjustment. 


» 























































































































ELECTRICAL EQUIPMENT 


309 


LIGHTING 

Lor automobile headlights, side lamps, tail lamps, and general 
illumination, electric lighting has superseded all other systems. In 
the best electric-lighting systems the current is supplied by a dynamo 
driven constantly by the engine, with a storage battery auxiliary. 

Incandescent Lamps. Tungsten and Other Filaments. Incan¬ 
descent lamps are usually provided with tungsten filaments. These 
filaments are much shorter and much stronger than in standard 
lamps, a condition that is further contributed to by the necessities 
of low voltage and high amperage, which require short and thick 
rather than long and thin filaments. A good tungsten lamp will 
afford 1 candle power of illumination for each 1.2 watts of current. 

Mazda Type. Fig. 184 shows the standard types of lamps gen¬ 
erally used. These are Westinghouse Mazda lamps for 6 volts, 
those at the left being 15 c.p. headlight lamps; the next two, 6 c.p. 



Fig. 184. Westinghouse Lamps—Head, Side, and Tail 


side-light lamps; and the smallest one is a 2 c.p. size designed for the 
tail light, meter light, and for interior lighting of closed cars. At 6 
volts, the 15 c.p. lamps require 2.5 amperes, the 6 c.p. side lights 1.25 
amperes, or where 4 c.p. lamps are employed—a better size for the 
purpose—.85 ampere; the 2 c.p. lamps take .42 ampere. The larger 
lamps have the filament in the form of a spiral coil occupying the 
minimum space so that the whole source of light can be placed at 
the exact focus point of the paraboloidal reflector. 

Bosch Type. Fig. 185 shows the Bosch lamps, which are of 
special form. The headlight lamp at the right is of 25 c.p. and has 
the filament stretched horizontally across wire supports, while the 
side lamps of 8 c.p. have a loop of corrugated wire, and the tail lamp, 
of tubular form, a single filament running straight across it. Tail 
lamps are usually in series with the instrument lamp so that failure 
of the latter to light also indicates a failure of the tail lamp. 




310 


ELECTRICAL EQUIPMENT 


Lamp Voltages. When Edison was asked how he came to 
hit upon 110 volts as the standard for incandescent lighting, 
he said he “just guessed it”. Evidently the 6-volt standard 



Fig. 185. Bosch Type Automobile Incandescent Bulbs 



came about in pretty much the same way. It is not practicable 
to operate small lamps at a high voltage, as the lamp of that type 
requires a long slender filament. Many manufacturers of starting 
apparatus have deemed it necessary to employ a higher voltage, but 

the lamps are usually run at 6 volts, so that 
the batteries employed are accordingly 
some multiple of 3, as 6, 9, or 12 cells, 
giving 6, 12, 18, or 24 volts. Where more 
than three cells are used, this necessitates 
operating the lamps from a part of the 
battery, which is not advantageous, as it 
involves discharging the battery unevenly. 
As a battery capable of delivering current 
at 12 volts weighs and costs about 35 per 
cent more than one giving current at 6 volts 
and the attention required is greater, the 
lower voltage is generally favored. 

Lighting Batteries. The only type of 
batteries suitable for electric lighting—except for very small tail 
lamps, which can be successfully kept in operation by dry cells—are 
storage batteries of the lead types, as described in Part VIII. 


Fig. 186. Typical Electric 
Automobile Headlight 








ELECTRICAL EQUIPMENT 


311 



Fig. 187. Section of Fig. 183 


Reflectors. Much attention has been directed to the problem of 
defining the best type of reflectors for automobile headlights, and the 
conditions of lighting by acetylene 
gas have been determined to be 
very different from those involved 
when electric lighting is used. 

Parabolic Type. A typical 
electric headlight for automobile 
use is that illustrated in Fig. 186. 

The plain form affords a mini¬ 
mum tendency to catch dirt and 
mud and greatly simplifies clean¬ 
ing. The position of the lamp 
is adjusted to give correct focus, 
as this is essential to give a 
properly projected beam of light 
ahead on the road. 

Comparison of Parabolic with 
Lens Type. The reflector in the 
foregoing lamp is of the deeply 
parabolic metal type, illustrated 
in Fig. 187. The advantage of 
this type of reflector is that it 
intercepts a much larger propor¬ 
tion of the light rays from the 
lamp than the lens-mirror type of 
reflector. Fig. 188. 

Types for Various I^ocations. 

Fig. 189 -a, -h, -c, -d, and -e show 
the usual types of lamps em¬ 
ployed. These are, in the order 
given, an outside side lamp, flush- 
type side lamp, two types of elec¬ 
tric tail lamps, and a cowl or dash 
lamp for illuminating the instru¬ 
ments, such as the ammeter, oil Fig. 188. Mangin Lens Reflector 
telltale, and the like. Fig. 189-/ shows a magnetic trouble-hunting 
lamp, the base of which attaches itself to any metal part of the chassis. 



























312 


ELECTRICAL EQUIPMENT 


Headlight Glare. The increased efficiency of electric headlights 
has brought with it, in far more aggravated degree, the blinding 



Fig. 189. Types of Side, Dash, Tail, and Trouble-Hunting Lamps 



glare first experienced with the acetylene lamps. Originally, strong 
headlights bothered pedestrians; but since the introduction of electric 

lighting, they have been objected 
to most strongly by automo- 
bilists themselves, because to 
the driver of an automobile, the 
blinding glare from the headlights 
of an approaching car means 
not only annoyance but danger. 
Acuteness of vision is whollv 

V 

destroyed for a period of thirty 
seconds or more during which 
only a slow-down to a walking 

pace will insure absolute safety to 
Fig. 190. Type of Headlight Dimming Switch automobilist, as a pedestrian 

or the usual black and lampless buggy are practically invisible. 






ELECTRICAL EQUIPMENT* 


313 


Dimming Devices. Owing to the fact that glare and illumina¬ 
tion are so closely related and that there is no objection to glare on 
deserted country roads where the necessity for road illumination is 
greatest, permanently dimmed lights are naturally not practicable. 



Fig. 191. Wiring Diagram of Parallel Control for Dimming Headlights 
Courtesy of Horseless Age, New York City 


What is required is a device under the control of the driver, so 
that either the full illuminating power of the head lamps or a subdued 
or dispersed light, free from glare, may be had as required. 

A great many fundamentally different devices have been offered 
as a solution of the problem. While differing radically, practically 



Fig. 192. Wiring Diagram of Series Control for Dimming Headlights 
Courtesy of Horseless Age, New York City 


all of them may be classed under two heads, i.e., electrical and 
mechanical. 

Electrical Devices. One of the simplest of this class that has met 
with considerable favor is nothing more nor less than a resistance 
that may be inserted in the circuit of the headlights by turning a 










































































314 


ELECTRIC'AL EQUIPMENT 


small switch, mounted either on the steering wheel or in some other 
easily accessible location. This cuts the voltage down and causes 
the lamps to burn a dull red, instead of the filaments being the daz¬ 
zling white reached at full incandescence. A dimmer of this type is 
shown in Fig. 190. An equally simple and practical device is a switch 
to throw the headlights into series for a dim light and back into par¬ 
allel again when full illumination is desired. \\ ith the series connec¬ 
tion, the current must pass through both lamps successively and each 
bulb thus receives but half the voltage and, as even a comparatively 



Fig. 193. Section of Hall Double Headlight 



Fig. 194. Jeffery Double Filament Lamp 


slight drop in voltage causes the efficiency of an incandescent lamp to 
fall off very markedly, the same result is attained. It is equivalent 
to burning a 6-volt lamp on a 3-volt current. With the normal, or 
parallel, connection, the current flows through each lamp separately, 
and both receive the full voltage of the battery so that they burn at 
full brilliance. A switch of this kind is marketed by the Cutler- 
Hammer Company. Fig. 191 illustrates the connections for parallel 
arrangement, or full illumination, switches D and B being closed and 
the button .1 pulled out to make C contact with its lower set of 
























ELECTRICAL EQUIPMENT 


315 


connections. Fig. 192 shows the connections for series burning, 
effected by pulling out button B and pushing in A, this closing 
switch E, opening D, and contacting C with the upper connections. 

The use of two bulbs in each headlight is also commonly resorted 
to, the method of effecting this being shown in Fig. 193. The second 
bulb is of the size ordinarily employed for side lights and is, moreover, 
entirely out of the focus of the reflector, so that the diminished light 
produced is entirely without glare and is mostly diverted downward. 

A similar end is attained by the use of two filaments in the same 
bulb, as shown in Fig. 194. The lower filament in this case is 
employed for full illumination, and the upper, which is out of focus, 
for the dimmed light. This has the disadvantage that the burning 
out of either one of the filaments makes it necessary to replace the 
lamp, while both filaments also require the same amount of current. 

PRACTICAL ANALYSIS OF TYPES 

EXPLANATION OF WIRING DIAGRAMS 

Significance of Symbols. To be successful in running down 
the cause of defection in a ‘starting and lighting system on a car 
involves, first of all, a knowledge of the most likely places to seek the 
trouble. Unless the trouble is very apparent or becomes so upon 
making the simplest tests, a process of elimination must be carried 
out, and, to do this with any degree of system, the trouble hunter 
must be perfectly familiar with wiring systems in general. To the 
uninitiated, wiring diagrams are nothing more than a jumble of lines, 
queer figures, and confusing signs. Familiarity with these signs, in 
consequence, is the first thing to achieve. Their direct bearing upon 
the varying relation of the essentials described in the introductory 
on Electrical Principles, Part I, will at once be apparent. 

Current Direction. The plus and minus, or positive and nega¬ 
tive signs, -f positive, — negative, scarcely call for any extended 
explanation. They indicate the direction in which the current 
flows. It is of the utmost importance, where the manufacturers’ 
directions are to connect certain apparatus with a given wire to the 
plus, or positive, side, and another wire to the negative, that these 
instructions be followed explicitly. Otherwise, the apparatus either 
will refuse to work or it may be damaged, as in the case of a storage 
battery on which the connections have been reversed. Wherever 


316 


ELECTRICAL EQUIPMENT 



Positive 


Negative 



Fig. 195. Battery, Either Storage or Dry Cells 



Fig. 196. Generator, Commutator, and Brushes 



Fig. 197. The Proper Method of Showing a Coil Which Surrounds an 
Iron Core but Very Seldom Used on Delco Drawings 



Fig. 198. The Method Used in Showing a Coil Where There Is No 
Chance of Confusion—Used in Field Coils, Ignition Coils, Etc. 



Fig. 199. The Method Used to Show Resistance Such as a Resistance 
Unit and Charging Resistances 



Fig. 200. 

Fig. 201. 

Fig. 202. 


Ground Connection Where the Wire Is Connected to the 
Chassis, Engine, or Generator 

Contact Points Such as in Switches, Distributors, Etc. 


Method Used to Show Lighting Switches 


Fig. 203. Primary and Secondary Windings of an Ignition Coil 


Fig. 204. Condenser 




Fig. 205. Upper Showing Crossed Wires not Connected. Lower 
Showing Connection in the Wiring 



Fig. 206. .Motor Commutator and Brushes with Brush Lifting Switch 





















ELECTRICAL EQUIPMENT 


317 


it is necessary that the current flow through a piece of apparatus in 
a certain direction, the manufacturer stamps plus and minus signs 
at the terminals. 

Battery; Generator. A battery, regardless of its type, is always 
shown by alternate heavy and light lines, as indicated in Fig. 195, 
each pair of lines representing a cell, so that the number of cells in 
the battery may be told at a glance. Other sources of current, 
such as generators, are indicated by a conventional sign consisting 
of a circle with two short heavy lines tangent to its circumference 
at opposite points and usually at an angle to the horizontal, as 
shown in Fig. 196. The origin of this sign will be apparent in its 
resemblance to the end view of a commutator with a pair of brushes 
bearing on it. This sign is also used to indicate a motor, in which 
case the letter IVI is inserted in the circle. 

Coils. Coils which are wound on an iron core are generally 
indicated by a conventional sign consisting of a few loops of wire, 
as in Fig. 197, but this is only the case where such a coil occurs at a 
place in the circuit where there might be a chance of confusion in 
identifying it. Where there is no possibility of confusion—as in 
the case of the windings of a generator or motor, ignition coils, and 
the like—the sign shown in Fig. 198 is often used. Where the lines 
are heavy, a coarse wire, such as is employed for series windings of 
generators or motors, or the primary winding of an ignition coil, 
is intended. 

Resistance. Resistance in a circuit is usually shown by an 
arbitrary sign. Fig. 199, similar in outline to a piece of the cast-iron 
grid frequently used in charging resistances, though sometimes 
shown as a coil and marked ^‘resistance”. 

Grounds. The sign of a ground connection is the inverted 
pyramid of short lines. Fig. 200, and indicates that the circuit is 
grounded. This may be either by a wire directly connected at 
some point with the frame, as in the case of the storage battery, 
or it may be through an internal ground connection in the apparatus 
itself, as in the lamps and sometimes the generator or motor, the 
connection being made simply by fastening them in place. In any 
case, the sign indicates that the circuit is completed through a ground. 

Contacts. There are a number of signs employed to indicate 
contact points, switches, and the like, and, where they are not of an 


318 


ELECTRICAL EQUIPMENT 


arbitrary character, such as Fig. 201, which shows contact such as 
used in switches, distributors, etc., and Fig. 202, which indicates a 
lighting switch (Delco diagrams); they usually will be found to 
bear sufficient resemblance to the apparatus itself to make their 
identification easy. 

Induction Coil. Fine lines indicate a generator shunt mnding, 
the secondary of an ignition coil, or the coil of a relay or cut-out. 
The primary and secondary windings of an induction coil as 
used for ignition are indicated by a fine and a coarse coil sign, as 
in Fig. 203. 

Condenser. A condenser with its overlapping plates is shown 
in Fig. 204. 

Crossed Wires. To show wires that cross one another without 
making connection, a half loop is made at that point to show that 
the wires do not touch, as in Fig. 205, while wires that are connected 
are showm by a black dot at the junction. 

General and Special Usage. While these signs are not uni¬ 
versally used in exactly the form showm here, their employment is 
very general and in the majority of cases, such as the positive and 
negative, battery, ground, generator, induction-coil windings, and 
coil signs, they are never changed. In some instances special signs 
are employed, such as that shown in Fig. 206, wiiich indicates the 
motor commutator of the Delco single-unit machine or dynaTnotor, 
and shows the special brush lifting switch. Incandescent lamps 
are almost ahvays indicated by small circles, though the lamp itself 
is sometimes drawn in. As a matter of fact, very little system is 
followed by different makers in making these wiring diagrams. In 
an effort to simplify its reading to the uninitiated, a diagram will 
sometimes picture most of the apparatus in such form that it will 
be recognized from its resemblance to the original, including the 
battery, generator, lamps, and the like, using only signs for showing 
coils and ground connections; others go to the opposite extreme and 
show^ nothing but signs. 

Diagrams for Single=Wire System 

Buick=Delco Type. For purposes of illustration a very simple 
diagram is selected. Fig. 207. This is the Delco single-unit system 
as employed on an earlier model of the Buick. Starting at the left 


ELECTRICAL EQUIPMENT 


319 


side of the diagram, 
the generator is shomi 
with its shunt-field 
winding, one brush of 
the generator and the 
shunt coil being 
grounded. This is a 
complete circuit, but, 
as the shunt coil has a 
high resistance, only a 
very small part of the 
current flows through 
it. The series wind¬ 
ing of the generator 
is shown at the top 
and the explanation 
that this is a ^Teverse’’ 
series coil means that 
it is wound to have a 
polarity opposite to 
that of the shunt coil. 
It accordingly opposes 
the shunt coil at the 
higher speeds and 
serves to regulate the 
output of the gener¬ 
ator. This is the 
familiar bucking coil 
or 'Reversed com¬ 
pound winding”. 

To reach the bat¬ 
tery, the current from 
the generator must 
pass through the auto¬ 
matic cut-out, the two 
windings and the con¬ 
tact points of which 
are shown a little 



fig. 207. Wiring Diagram for Delco Single-Unit Single-Wire System 
























320 


ELECTRICAL EQUIPMENT 


further to the right along the top line. If the ammeter on the dash 
fails to register any charging current when the engine is running at a 
speed equivalent to 10 miles an hour or more, the automatic cut¬ 
out would be the first place to seek a break in the system. Under 
normal conditions of working, the cut-out closes the circuit as soon 
as the generator reaches a certain speed and the 3-cell storage bat¬ 
tery, one side of which is grounded, is then being charged, the current 
entering at the plus or positive terminal and returning by way of the 
minus terminal or pole through the ground connection. (In some 
systems, such as the Gray & Davis, the frame of the car is the posi¬ 
tive side of the circuit.) 

Between the generator and battery circuits is shown the start¬ 
ing-motor circuit. The width of the lines employed indicates that 
very heavy conductors are used in this circuit and they are neces¬ 
sary owing to the extremely heavy currents handled. The series 
winding of the motor field is also short and of heavy wire. The 
upper brush of the motor being in a raised position indicates that 
the motor is brought into operation through a switching brush, and 
when this switch is closed to start, one of the generator brushes is 
raised from the commutator. This completes the generating, 
starting, and controlling circuits, all of which are showm to the left 
of the battery. The relative difference in thickness between the 
wires of these circuits at the left and those at the right for the lighting 
and ignition show the difference in the amount of current handled 
by the two. The double set of contact points at the center along 
the top line indicate the dash switch—turning this to the left giving 
the magneto connection ilf , while throwing it to the right B puts in 
the battery of six cells shown just a bit further to the right in the 
ignition circuit. To the left of this dash switch a tap has been 
made for the lights, the three circuits of which, head, side, and tail 
are indicated but not completed, the draftsman often taking it fo-r 
granted that complete detail connections are unnecessary. Another 
instance of this will be seen just below the lighting switch, the 
leads from the high tension distributor (four indicating a 4-cylinder 
motor) ending up a short distance from it, as it is obvious that they 
lead direct to the spark plugs. 

The primary and secondary windings of the induction coil 
(ignition)—the former of which is grounded through a resistance 


LIGHTS 


/ 


ELECTRICAL EQUIPMENT 


321 




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t: V) 

>yz 




■«tN^ 


'v 








*-5 

o 

OfTj 


Q 


IfP 

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JLMtHt T/KL 


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Fig. 208. Wiring Diagram for Delco Single-Unit System on the Auburn Six-40 





















































































322 


ELECTRICAL EQUIPMENT 


unit and the timer, and the latter directly—are plain. But it also will 
be noted that a condenser is shunted around the sparking contacts of 
the timer, one side being connected to the contact terminating the 
positive side of the circuit, while the other is grounded. The function 
of a condenser here is to absorb the charge or surge of current due to 
the sudden opening of the contacts (breaking of the circuit) and to 
prevent the formation of an arc which would burn the contact points 
away rapidly. Badly pitted or burned contact points accordingly are 
an indication that the condenser has broken down or become discon¬ 
nected from the circuit. This also will be evident from the excessive 
sparking at these contacts when the engine is running. The secondary 
winding of the coil is grounded directly. At the right-hand end of 
the diagram is seen the independent circuit of the dry-cell battery 
for emergency use in starting. The current from this battery passes 
through a relay coil the contact points of which are also provided 
with a condenser for the purpose already explained. 

Auburn=Delco Type. The wiring diagram of the Delco light¬ 
ing, starting, and ignition system of the Auburn, Model 6-40, Fig. 
208, is more completely shown than the one to which reference was 
made above, in that all the switching connections are indicated and 
the lamp circuits have been carried out. Examination will also show 
that it differs in other respects as well. For example, instead of a 
bucking-coil type of regulator winding, the generator output is con¬ 
trolled through a variable resistance in the shunt-field circuit, the 
amount of resistance increasing with the speed. As the current 
through the shunt coil decreases with the increase in resistance, the 
fields are weakened and the generator output falls off. 

Instead of the usual magneto-and-battery switch a special form 
of combination switch is shown in this wiring diagram which controls 
two circuits simultaneously, the generator-battery circuit and the 
circuit breaker-ignition coil circuit. These are discussed further 

in the main Delco section. 

Diagram for Two=Wire System 

Chevrolet=Auto=Lite Type. The wiring diagrams already 
explained are what are known as ^‘single-wire’’ or grounded systems, 
there being but a single wire connecting any piece of apparatus to 
the source of current supply, the return side of the circuit being 
through the frame of the car. While usually referred to as the 


ELECTRICAL EQUIPMENT 


323 


'Teturn” side of the circuit, the steel sections forming the frame of 
the car may be utilized for either the positive or negative side. 



The wiring diagram, Fig. 209, which is that of the Auto-Lite 
system as applied to the Chevrolet is of the two-wire type. With 


Fig. 209. Wiring Diagram for Auto-Lite System on Chevrolet (Royal Mail and Baby Grand ^Models) Showing Two-Wire Connections 























































































































324 


ELECTRICAL EQUIPMENT 


H 

X 






































































































































































ELECTRICAL EQUIPMENT 


325 


the exception of the ignition circuit, which is always grounded 
owing to the spark plugs completing the circuit by being screwed 
into the cylinder heads, it will be noted that two-wire connections 
are made. The ignition circuits are completed by a ground at the 
battery for the starting current, and by another at the generator 
for the current when running. The circuit breaker is also grounded. 

Jeffery=Bijur Type. The two-wire system of the Bijur as 
installed on the Jeffery Chesterfield Six is shown in Fig. 210. All 
lighting circuits are fused and there is also a fuse in the ground 
connection for the ignition. The numbers referring to the various 
circuits indicate the proper size of wire used in each circuit. This 
is an important item in every starting and lighting system, as, 
where any wires have to be replaced owing to mechanical or elec¬ 
trical injury, they must always be replaced with wire of the same 
size and character of insulation, as otherwise, further and more 
serious trouble is apt to follow. Thus, for the starting circuit No. 0 
(Browm & Sharpe gage) cable is employed; for the charging circuit 
between the generator and battery No. 10; for the lighting circuits 
No. 14, which is the size ordinarily employed for incandescent-lamp 
circuits in house wiring; and for the horn No. 18. ‘‘Duplex” in 
this connection means that both wires of the circuit are enclosed in 
the same braided insulation. “Loom” is tubular fireproof insula¬ 
tion through which the wires are passed to afford further protec¬ 
tion, and the sizes vary in accordance with the size of the wires. 

USE OF PROTECTIVE AND TESTING DEVICES 

Circuit Breaker. This is a protective device, the theory of 
which will be clear at once upon referring back to the explanation 
of an electromagnet in the introductory chapter. It consists of an 
electromagnet with a movable armature adapted to open the cir¬ 
cuit by its movement, the latter being controlled in turn by the 
amount of current flowing in the circuit. 

By referring back to the diagram. Fig. 208, and noting the par¬ 
ticular function of the circuit breaker, an excellent example of the 
value of ability to trace wiring diagrams at a glance can be shown. 
Assume that when the button M of the combination switch. Fig. 
212, is pulled out, the ignition fails to work. An examination of the 
diagram shows that when M is pulled out, its lower contact bridges 


326 


ELECTRICAL EQUIPMENT 


the wires No. 1 and No. 7 connecting the generator with the battery. 
At the same time its upper contact bridges a pair of terminals which 
insert the circuit breaker and the ignition coil on cable No. 8 in the 
circuit. Further examination of the ignition or lighting circuits 
shows that throwing on any one of these circuits includes the circuit 
breaker. The function of the latter is to prevent the discharge of 
the battery when the generator is standing idle or running too 
slowly to generate the necessary voltage to charge the battery. It 
also serves to protect the lamps, ignition coil, and horn from dam¬ 
age, in case any of the wires leading to these essentials should become 
grounded, and in this role takes the place of fuses and fuse block. 
As it requires 25 amperes to operate the circuit breaker in this 
particular instance, it is not affected by the normal operation of the 
lamps, ignition, or electric horn. But in the case of a short circuit 
or ground, the whole output of the battery would pass through the 
circuit breaker, moving its armature and breaking the contacts, 
which open the circuit. This cuts off the current and a spring 
brings the contacts together again, when the operation is repeated, 
causing the circuit breaker to vibrate and pass an intermittent 
current of comparatively small value. While it will not break the 
circuit on less than 25 amperes, it will continue to vibrate on a 
current of 3 to 4 amperes. Its continued vibration is an indication 
that there is a ground in one of its circuits. Hence, no attempt 
should be made to stop this action by tightening the spring of the 
circuit breaker, but by locating the ground. 

Tracing for Grounds. This can best be done by a process of 
elimination in which a knowledge of the wiring diagram will come 
handy. Referring again to Fig. 212, if the circuit breaker operates 
when switch M of the combination is pulled out, it will be apparent 
that the ground is located in either the main generator-battery 
circuit, or the ignition-coil circuit, as it will be seen that the lower 
contact member of the switch throws the former in the circuit and 
the upper contact member throws the latter in the same circuit 
with the circuit breaker. If pulling out M does not set the circuit 
breaker operating, but pulling out T does, this would indicate a 
ground in the circuit of the tail and cowl lights, while the operation 
of the circuit breaker on pulling out either S or 77, would indicate 
that the ground was located in the wiring of either the side lights 


ELECTRICAL EQUIPMENT 


327 


or the headlights depending on which switch caused the circuit 
breaker to respond. The combination switch B serves to connect 
the generator and storage battery in the circuit, the same as M, 
but it also includes the 5-cell dry battery in the ignition circuit. 
It will be noted that the distributor has six spark plug leads, indicat¬ 
ing a 6-cylinder engine, also that the connection of the ignition 
timer in the circuit is somewhat different from the previous diagram, 
Fig. 207, in which it is on a branch circuit of the storage battery, 
whereas in this instance it is also in the generator circuit. 

Having determined the particular circuit in which the fault lies 
it is next necessary to narrow it down to exactly the defection that 
is causing the ground. For work of this nature nothing handier 
can be devised than the simple testing set which is described later 
and which may be assembled at nominal expense. 

Fuses. The lighting circuits of many cars are 
provided with fuses, designed to protect the battery. 

These fuses are usually of the enclosed type, con¬ 
sisting of a glass tube with brass caps at each end 
to which the fusible wire is connected, as showm in 
Fig. 211, Usually when a fuse “blows”, due to 
excessive current caused by a ground or “short”, 
the wire melts entirely and this will be visible. But 
at times it will simply melt at the soldered connec¬ 
tion and not show any fault. In beginning a test it is well to go over 
the fuses first, holding one of the test points of the lamp circuit on 
one end of the fuse and touching the opposite end of the fuse with the 
second test point. Failure of the lamp to light will indicate the defec¬ 
tive fuse. On systems employing a circuit breaker as shown in the 
wiring diagram. Fig. 208, no fuses are necessary as the circuit breaker 
serves the same purpose and also gives an audible signal of trouble 
by its buzzing. Upon finding an open circuit where one is supposed 
to exist as shown on the wiring diagram, it is always well to verify 
this by again testing the trouble lamp itself before beginning to 
tear anything out. The rough handling to which such a lamp is 
subjected frequently causes the filament to break. 

If immediately upon being replaced, a fuse again blows, it may 
indicate that one of the lamp circuits of the car is short-circuited or 
the lamp on that circuit is defective, having become short-circuited. 



Fig. 211. Typical 
Fuse 


























328 


ELECTRICAL EQUIPMENT 


the remedy being a new bulb. In some systems, fuses are used in 
other circuits, as in the case of the Bosch-Rushmore in which there 
is a fuse on the switch block to protect the main shunt winding 
of the generator. The blowing of this fuse indicates a broken 
battery connection, such as a loose or broken terminal or a cor¬ 
roded battery connection on the cells themselves. 

Handy Test Set. Take a porcelain base socket, screw it to a 
piece of board to form a base. Connect one side of this lamp socket 



Fig. 212. Handy Testing Set 


to a standard screw plug. Procure two pieces of brass or steel rod 
and file or grind them to a long tapering point. These rods should 
be about 6 inches long and tapering half their length to a sharp 
point. Connect the other side of the lamp socket to one of these 
points and connect the second point to the other terminal of the 
screw plug. Ordinary lamp cord can be used for the connections. 
For fastening to the test points it should be bared for several inches, 
wrapped solidly around the metal rods at their blunt ends, and 






















ELECTRICAL EQUIPMENT 


329 


soldered fast in place. The joints should be heavily wrapped vith 
tape or covered with other insulating material to form a handle, 
as shown in the illustration, Fig. 212, As shown by the diagram 
forming part of this illustration, it will be seen that the lamp is in 
series with one of the points, but that when the circuit is closed by 
bringing the two points together, the lamp is in multiple with the 
main circuit. The lamp should be of the carbon-filament type 
owing to its greater durability. As a lamp of 
this type of 16 c-p. only consumes a little over 
50 watts at 110 volts, or approximately half an 
ampere of current, there is no danger of injuring 
any of the apparatus on the automobile through 
its use. Sufficient cord should be allowed on 
either side of the lamp to permit of connecting 
it up with the outlet conveniently. 

In using this test outfit, the two test points 
are pressed on places between which no current 
should pass, and if the lamp lights it indicates 
that there is a ground between those points. 

For example, in Fig. 208, if there were a ground 
between the generator and the switch so that 
no current reached the latter, the lamp would 
not light when the test points were placed on 
terminals 1 and 7 of the diagram, the gener¬ 
ator then being in operation. But a little 
searching along this circuit would soon show 
where it was grounded, thus making it easy to 
locate the break or ground. Fig. 213 is a graphic 
illustration of a ground causing a short circuit, 
due to worn insulation. Much more satisfactory results can be 
obtained with a test set of this nature than with either an expensive 
hand ringing magneto test set, or with a set consisting of a bell or 
buzzer and a few dry cells. The former is unnecessarily expensive for 
the purpose while the latter has not sufficient potential to force the 
current through grounds or breaks that present too great a resistance, 
whereas the higher voltage of the lamp test set will cause it to give 
an indication where the battery set would not. With the aid of 
such a set, every circuit shown on even the most complicated of 



Fig. 213. Diagram of 
Ground or Short 
Circuit 

Courtesy of Gray and 
Davis Company 










































330 


ELECTRICAL EQUIPMENT 


wiring diagrams can be tested in fifteen to twenty minutes, maybe 
less, depending upon how accessible the connections of the various 
circuits happen to be. 

If preferred, owing to greater convenience, a 6-volt lamp can 
be used in the socket of the test set and current from the car battery 
can be utilized for testing. In case the car happens to have either 
a 12-volt or a 24-volt system, connect lamp terminals to but three 
of the cells. Should the lamp not light to full incandescence it 



Fig. 214. Portable Combination Volt-Ammeter for Testing 

will indicate a weak battery. Full directions for the care of storage 
batteries are given in the resume in Questions and Answers, and 
also in the article on Electric Automobiles. In case the battery 
does not respond to any of the ordinary methods of treatment given 
there, it will usually be found preferable to refer it to the nearest 
service station of the battery manufacturer. This is particularly 
the case wLere after refilling with distilled water to the proper 
level and slowly recharging, the battery does not increase in voltage 
and specific gravity reading with the hydrometer. 


















ELECTRICAL EQUIPMENT 


331 


Always Test the Lamp. Whether a standard 110-volt lamp 
or one of the 6-volt type (for which an adapter may be necessary 
to fit the standard socket) is used, it is a good precaution always 
to test the lamp itself before going over the wiring on the car. This 
will avoid the necessity for blaming things generally after failing 
to find any circuit at all—after fifteen miutes of trying everything 
on the car—due to the lamp 
having a broken filament or 
one of its connections hav¬ 
ing loosened up. 

Special Testing Instru¬ 
ments. For the garage that 
claims to be fully equipped 
to give all necessary atten¬ 
tion to the electrical system 
of the modern car, some¬ 
thing more than the simple 
lamp testing outfit is nec¬ 
essary. Portable volt- 
ammeters such as shown in 
Fig. 214 are made specially 
for this purpose. This is 
a Weston combination volt- 
ammeter, the voltmeter 
being provided with a 0-30, 

0-3, and 0 to y o scales for 
making voltage tests, to¬ 
gether with three shunts 
having a capacity of 0-300, 

0-30, and 0-3 amperes, re¬ 
spectively, which are used 
in connection with the 

yV-volt scale for making current measurements. A special set 
of calibrated leads for use with these shunts is also provided. 
Wfith the aid of such an outfit, accurate tests can be made covering 
the condition and performance of every part of a starting-lightin g 
and ignition installation. For example, a starting system may 
be otherwise in perfect working condition, but its operation causes 



Fig. 215. 


Diagram Showing 3-Volt Scale Connected 
across a Circuit 




















332 


ELECTRICAL EQUIPMENT 


such an excessive demand on the storage battery that the generator 
is not capable of keeping the latter sufficiently charged. Generator 
tests, which are described later, having failed to show anything 
wrong with the dynamo, a test of the starting motor, using the 
0-300-ampere shunt of the instrument would doubtless show that 
an unnecessarily large amount of current was being demanded 

by the motor for its oper¬ 
ation, and indicate a fault 
in the latter. 

Voltage Tests. When 
the instrument is used as 
a voltmeter it is neces¬ 
sary to select the proper 
scale for the eireuit, and 
if there is anv doubt it 

t/ 

is well to start with the 
30-volt scale. For test- 
ing individual cells of the 
storage battery the 3-volt 
scale would naturally be 
used, while for testing 
the entire battery, the 
30-volt scale would be 
the proper one to apply. 
The proper method of 
connecting the voltmeter 
to the circuit is shown 
by the diagrams. Figs. 
215 and 216. It is nec¬ 
essary to connect the 
positive side of the meter 
to the positive side of the circuit and the other terminal to the 
negative. Where the polarity of the circuit is not known, this 
can be readily determined by a trial reading. If the pointer moves 
to the right, the connections are properly made; in case it moves 
to the left, it will be necessary to reverse the connections, which 
should be done at the circuit terminals and not at the meter, to 
avoid any aceidental short circuits. 



Fig. 216. Diagram Showing 30-Volt Scale Connected 
across Storage Battery Terminals 










































ELECTRICAL EQUIPMENT 333. 

Ammeter Readings. When using the ammeter to determine 
the amount of current consumed by any of the apparatus, such as 
the starting motor or the lamps, it is necessary to first select the 
proper shunt. Should the value of the current to be measured be 
unknown, it is well always to start with the 300-ampere shunt 

f ' i 



Fig. 217. Diagram Showing Method of Connecting Ammeter to 300-Ampere Shunt 


and then insert the 30-ampere shunt in case the reading shows the 
current to be less than 30 amperes. These shunts are connected 
in the manner shown by Fig. 217, and as will be plain from this 
diagram, all shunts are connected in the circuit in a similar manner. 
The connections always remaining the same, it is only necessary 













































334 


ELECTRICAL EQUIPMENT 


to substitute the different shunts as required by the circuit to be 
measured. If the polarity be reversed, it is only necessary to 
shift the connections from the ammeter to the shunt which should 
be done at the latter, there being no necessity to change the con¬ 
nections of the shunt itself to the circuit. The 300-ampere shunt 
must always be used for measuring the starting current, as the 
latter will rarely have a value of less than 200 amperes when the 
switch is first closed owing to the necessity of exerting great power 
at first to overcome the inertia of the gasoline engine, particularly 
at a low temperature when the lubricating oil has become gummed. 
Cables of the same size as those employed on the starting-motor 
circuit of the car should be provided for connecting up the shunt 
to make the tests. The 30-ampere shunt is employed for measuring 
the charging current to the battery, while the 3-ampere shunt is used 
for the individual lighting circuits or for the primary ignition current. 

In the following section, the various systems in general use 
are described in detail. 

AUTO=LITE SYSTEM 
Six=Volt; Two=Unit; Single Wire 

Generator. Three types of generators are furnished. One 
has a permanent magnetic field and resembles a magneto but can 



Fig. 218. Auto-Lite Generator of the Bipolar Type 
Courtesy of Electric Auto-Lite Company, Toledo, Ohio 


be distinguished by its drive and governor, as well as the fact that 
it is fitted with a commutator and brushes instead of a contact 



ELECTRICAL EQUIPMENT 335 


breaker and distributor. It has been supplied chiefly for installation 
on cars which were not originally fitted with electric lighting and 
starting systems. The second is somewhat similar in design but 
has an excited field, the field magnets being of U-form and laminated; 
this type of generator is used on the Overland Model 82. There 
is a single field winding, as shown in Fig. 218. The third is a four- 
pole machine having two wound poles, usually termed salient poles 
and two consequent poles, which carry no windings. A diagram¬ 
matic section of this generator is shown in Fig. 219. The salient 
poles are those in the vertical plane while the consequent poles 


Upper series 
winding: 
Negative or 
grounded 
terminal 

Negative brush 


Positive brush 

Positive terminal 
leading to 
circuit breaker 
Lower series 
winding 



Upper shunt 
winding 


Shunt 

connection 

Armature shaft 

Commutator 

Armature 


Lower shunt 
winding 


Fig. 219. Diagrammatic Section of Four-Pole Auto-Lite Generator 


are horizontal. The diagram also shows the commutator, brushes, 
and the compound winding of the generator. 

Regulation. The current output of the permanent-field type is 
regulated by a centrifugal governor; it should not drop below 10 
amperes, nor exceed 12 amperes. Any falling off can be remedied 
frequently, simply by cleaning the governor out thoroughly with 
gasoline, allowing it to dry, and giving it a drop or two of light oil; 
if this does not increase the output sufficiently, the weights can be 
moved inward an eighth of an inch or more to decrease the pressure 
on the springs mounted in the governor arms. Fig. 220. This per- 








































336 


ELECTRICAL EQUIPMENT 


mits the generator to run at a higher speed. The regulation of the 
other type is inherent and is due to the series windings of the field 

being made in the reverse direction to 
that of the shunt windings, so that their 
polarity is reversed. This is commonly 
referred to as a bucking coil, also as a 
differential winding. As the speed in¬ 
creases, the magnetizing effect of the 
shunt coils is opposed by this bucking 
winding and thus kept within safe limits. 
This type of generator is used on the 
Overland Model 80 and Model 81, be¬ 
sides other cars. 

Starting Motor. The starting motor 
is a series-wound multipolar type having four salient poles. Fig. 221 
(used on Overland Model 80 and Model 81). In this type the switch 
is.combined directly with the motor, being mounted in a housing at 
the left end as shown in Fig. 221. It is also fitted with a special lock¬ 
ing device, the details of which are illustrated in the sectional view. 
Fig. 222. One of the buttons on the control board on the steering 
column closes the circuit of the solenoid shown in this illustration; this 
causes the plunger to lift and release what is known as the gear- 
latch. The shaft carrying the switch also serves to shift the pinion 
on the end of the starting-motor shaft into mesh with the flywheel 
gear. A later and more widely employed type of Auto-Lite starting 
motor is shown in Fig. 223; this is installed on the Overland Model 



Fig. 220. Governor of Auto-Lite 
Permanent-Magnet Type 
Generator 



Fig. 221. Auto-Lite Starting Motor Used on Overland Models 80 and 81 


82 besides a number of other cars. It is known as the Bendix drive 
and is coming into very general use owing to its simplicity and its 





ELECTRICAL EQUIPMENT 


337- 


automatic operation which eliminates the necessity for gear-shifting 
devices actuated by the switch, when operating the starting motor. 
The armature shaft has a threaded extension provided with an 


Solenoid-operated 
gear latch 



Fig. 222. Sectional View of Auto-Lite Starting Switch and Gear Release 


outer bearing and carries a pinion. A weight is solidly attached to 
this pinion and the latter is loose enough on the shaft always to 



Fig. 223. Auto-Lite Starting Motor with Bendix Drive 


occupy the position shown with the weight underneath when the 
shaft is idle. The leading screw has a triple thread. On starting 
the electric motor the inertia of the weight causes it and the pinion 

















































338 


ELECTRICAL EQUIPMENT 


to be carried along the shaft and into mesh with the gear on the 
flywheel in which relation it remains until the engine begins to run 

t/ 

under its own power. This reverses the relation, the flywheel then 
driving instead of being driven, which automatically throws the 
pinion out of mesh. The coil spring shown is simply to take up the 
shock of starting and permits a slight play between the motor shaft 
and the threaded extension. Before the svdtch which is located on 
the footboards can be operated, a button on the control board must 
be pushed. This actuates a solenoid the plunger of which raises a 
latch, releasing the starting switch. 

Battery Cut=out. The battery cut-out is shown in Fig. 224. 
As already explained, the majority of electric systems on the auto¬ 
mobile must be provided with a cut¬ 
out to protect the battery when the 
generator speed falls below a certain 
point. It is frequently referred to as a 
circuit breaker, which it is in fact, 
though the circuit breaker is a protec¬ 
tive device used for another purpose, 
as has been mentioned. The cut-out 
may be compared to a check valve in 
a water supply line between a pump 
and a tank; the pump can force water 
into the tank against its pressure but, 
regardless of how great this pressure 
becomes owing to the filling of the tank, 
the water cannot run back through the pump when the latter is idle. 

In principle, the battery cut-out is simply a magnetically 
operated switch. When the current passes through its winding the 
armature is attracted and brings a pair of contact points together. 
These will be seen at the upper right hand at the point of the arrow. 
In the best-grade apparatus, these points are of platinum or platinum 
and iridium as the latter is proof against oxidation as well as cor¬ 
rosion and resists pitting under the electrical current better than 
any other metal. As it costs more than gold, silver, which is next 
best for the purpose, is frequently employed. The cut-out in this 
case is set to close the circuit and allow the generator to charge the 
battery when the engine is driving the car at 7| miles per hour, but 



Fig. 224. Auto-Lite Battery Cut-Out 
(Circuit Breaker) 
















ELECTRICAL EQUIPMENT 


339 


when the speed is dropping it does not open the circuit until it falls 
to 6 miles per hour. This is to prevent the cut-out from operating 
continuously when the car is running at its opening speed of TJ 
miles. The battery, however, governs to a large extent the running 
speed at which the cut-out will operate. When fully charged, 
owing to the higher resistance thus presented, the cut-out does not 
close the circuit until the car is running at 10 to 12 miles per hour. 
In case the cut-out is removed from the car for any reason, the 
latter must not be operated until a short piece of bare copper wire 
is securely connected from the wire terminal post of the generator 
to one of the brass screws in the name plate. 

Instruments. The instrument regularly supplied is a double¬ 
reading ammeter showing charge and discharge from 0 to 15 amperes. 
When lamps are off with car running at 10 miles per hour or over, 
it should indicate charge. 

Wiring Diagram. The connections are practically the same, 
regardless of the type of starting motor installed, so that the follow¬ 
ing description will cover all three of the Overland models men¬ 
tioned, Fig. 225. The ignition system is entirely independent of the 
starting and lighting system, although it appears on the diagram. 
The connections are as follows: Cable 12072, battery negative to 
motor terminal; cable 12073, battery positive to starting switch; 
wire 12236, starting switch to fuse block; wire 12066, fuse to positive 
ammeter terminal; wire 12066, negative ammeter terminal through 
fuse; wire 12069, to battery cut-out; wire 12068, generator positive 
terminal to cut-out. The battery negative is grounded at the end 
of cable 12072, while the cut-out is grounded to the frame through 
the wire 12906 and the generator is grounded at its negative ter¬ 
minal. This is an example of the frame of the car being employed 
for the negative side of the circuit, as compared with the Gray & 
Davis in which it is utilized for the positive side. While the ground 
connections of the lamps and horn are indicated as separate wires, 
in the case of the lamps the socket itself forms the ground connec¬ 
tion. The location of the various fuses and the relation of the 
various essentials of the system will be clear upon tracing the 
diagram. 

Instructions. While a car never comes into the shop to have 
its electrical equipment examined until some fault develops, and 


340 


ELECTRICAL EQUIPMENT 


the man who has to locate the trouble seldom has occasion to run 
the car in ordinary service, still it is important that he should famil- 


X 

3 

I 

iij 

o 

to 



I 


iarize himself with the instructions issued to the owner, in order that 
he may know at a glance whether these instructions have been 


'ig. 225. Auto-Lite Wiring Diagram for Overland Cars 







































































































































ELECTRICAL EQUIPMENT 


341 


carried out or not. It is safe to say that more than half the troubles 
that arise with this equipment are due to failure to follow instruc¬ 
tions in its use. The average motorist ordinarily pays little atten¬ 
tion to the workings of the apparatus until it goes wrong and then 
he is helpless. There is, however, another type—the man who' is 
given to tinkering. He is responsible for not a few of the problems 
that come into the garage, and familiarity with the manufacturer’s 
instructions will assist in tracing the result of his efforts. 

Chain Drive, The silent-chain drive of the generator should 
be inspected occasionally and any slack taken up by loosening the 
screw which holds the generator on its bracket, and moving the 
generator over by means of the adjusting screw. The chain should 
be just slack enough to have no strain on its links when the engine 
is not running. Although the initial stretch of the chain is taken 
out at the factory by running it under load, these chains will con¬ 
tinue to stretch slightly in service. After making the adjustment 
the holding screws should be re-tightened. 

Commutator and Brushes. The commutator is the most vul¬ 
nerable part of a direct-current machine. It should be examined 
first whenever there is any trouble with the generator, such as 
insufficient output of charging current, or with the starting motor, 
such as loss of power, the battery being in good condition. (No 
mention is made of battery instructions in this connection as the 
subject is fully dealt with in another volume, and in the summary 
following this section. The battery is, however, the cause of fully 
80 per cent of all electrical-system troubles and neglect is at the 
root of most of these.) 

The commutator is made accessible by the removal of a small 
plate—in this case, the name plate. If it is blackened and rough, 
the brushes first should be examined and trued up and the com¬ 
mutator should be smoothed down with fine sandpaper (never use 
emery cloth as it is metallic and will short-circuit the segments). 
The mica insulation should be carefully examined; if it is flush with 
the copper segments this is the cause of the roughened up brushes, 
and the mica should be undercut. Detailed instructions for smooth¬ 
ing the commutator, truing up the brushes and undercutting the 
mica insulation are given in connection with the Delco system. 
Any carbon dust from the brushes should be carefully blowm out 


342 


ELECTRICAL EQUIPMENT 


as this will tend to short-circuit the armature and field windings. 
See that the brush holders swing easily on the studs and that there 
is just enough spring tension on the brushes to make good contact 
on the commutator. Too much tension will cause unnecessary heat¬ 
ing and wear of the commutator and brushes. Keep the commu¬ 
tator and brush chamber free from dirt and grease. Never replace 
brushes with any but those supplied by the manufacturer. See 
that the brush holders are well insulated from their supports, replac¬ 
ing any of the insulating plates, bushings, or washers that may have 
become damaged. Should the battery or generator be disconnected 
do not run the engine until they are again connected. Should it be 
necessary to do so, connect a short piece of bare copper wire from 
the terminal of the generator to one of the brass screws in the name 
plate. 

Generator Tests. The following tests will be found an aid in 
locating failure of the generator. 

Field. To test the field coils, lift the brushes off the 
commutator and insert a piece of fiber or clean dry wood. 
Close the battery cut-out by pressing the finger on the contacts. 
The ammeter should then register about one ampere if the coils 
are all right. 

Armature. To test the armature, remove the driving chain and 
close the cut-out as before. This will motorize the generator and 
it should then run at 650 to 750 r.p.m., drawing 3 to 3| amperes, 
if its windings are in good condition. This refers to the generator 
on Overland Model 80 and Model 81. The hlodel 82 generator 
should run at 275 r.p.m. on a current of 2 to 2J amperes. 

Grounds. Tests for grounded windings in either the field or 
armature coils can be carried out with the aid of the testing-lamp 
outfit described. Remove the brushes, place one test point on a 
commutator segment and the other point on the armature shaft; 
if the coil is all right the lamp will not light. Each coil can be 
tested in succession in the same way. To test the field coils, lift 
one brush from the commutator and place the test points one on 
each brush holder; the lamp should light as this places the field coil 
in series with the lamp. 

In case any faults are located in the windings it will usually 
be found advisable to consult the manufacturer’s service station 


ELECTRICAL EQUIPMENT 


343 


oi* *ttic diroot^ as either armature or field winding is some¬ 

thing that is beyond even the best equipped of garages. 

Battery Cut=Out Tests. Failure of the battery cut-out to oper¬ 
ate will most frequently result from pitted or blackened contact 
points. Clean and true up with fine sandpaper which should be 
drawn back and forth between them while slight pressure is applied 
to the upper one, taking care to keep the sandpaper at right angles 
to the vertical plane of the points, as otherwise they will be put out 
of true. See that the faces of both points come together over their 
entire surface when pressed together with the finger. 

Operation. Test for operation by sending the current from five 
dry cells in series through the coil of the cut-out. The points should 
come together with a snap as soon as the circuit is completed and 
should hold fast as long as the current is on. This test should not 
be continued too long, however, as the dry cells will weaken. In 
case the armature is not attracted, leaving the points in the open 
position when the battery current is sent through it, inspect the 
connections from the binding posts to the coil. The wire is small 
and may have broken from vibration. 

Should no circuit be found through the coil with the dry bat¬ 
tery, try the test-lamp outfit on the 110-volt circuit, holding one 
point down on a binding post and just touching the other momen¬ 
tarily with the second point. If the lamp fails to light, there is a 
break in the coil and the cut-out should be returned to the manu¬ 
facturer. 

BIJUR SYSTEM 

6=VoIt; Two=Unit; Single= or Double=Wire, According to Make 
of Car. Also 12=Volt; Single=Unit 

Generator. The generator is a special reversible type. Due 
to the reversible characteristics of the machine it may be connected 
in either direction and it will assume the proper polarity for charging 
the storage battery. 

Regulation. This is the constant-voltage type, the regulator 
and battery cut-out being mounted directly on the generator. 
The principle of this method of regulation is to maintain the voltage 
of the generator constant, the current output depending on the 
resistance of the circuit and varying with the state of charge of 
the battery. This is accomplished by the use of a magnetic vibrator 


844 


ELECTRICAL EQUIPMENT 





r 





similar in principle to the ordinary electric bell, or buzzer, though 
it takes a different form. Fig. 226. H is the magnet winding, A the 
soft-iron core of the magnet, and G the vibrating armature, do 
prevent G from coming directly in contact with the pole piece on 
the upper end of A, a stop pin I is provided. C and F are the 
contacts, C being held against F by the tension spring E and is pulled 
away from F by the magnetic pull of coil H in armature G. These 
contacts are mounted on vibrating reeds (thin strips of spring brass) 
placed at right angles to each other. Contact C and its reed are 
attached to the armature G, and stop pins B limit the lateral movement 
of this contact. F and its reed are also mounted on an arm as shown. 

When a current flows through the magnet coil the armature 

G is attracted, automatically 
released by the breaking of 
the circuit, and again at¬ 
tracted so that it vibrates, 
the rate of vibration depend¬ 
ing upon the amount of cur¬ 
rent. As the vibrator is in¬ 
cluded in the fleld circuit the 
current in the latter is ac¬ 
cordingly pulsating, and as 
a fleld circuit, owing to its 
heavy iron core has consid¬ 
erable self-induction, the amount of current flowing through it will 
decrease in proportion to the rapidity of the vibration or pulsations. 
To prevent the field losing its excitation altogether every time the 
vibrator opens the circuit, the latter is not connected directly in 
circuit with the shunt winding of the generator, but is placed across 
the terminals of a resistance unit in series with the shunt field. 
This also prevents the arcing or heavy sparking that otherwise 
would result from the breaking of a circuit having so much induct¬ 
ance. Failure of a vibrating regulator is usually caused by the 
contact points sticking or fusing together owing to the heat. Mount¬ 
ing the points on reeds is designed to prevent this as the vibration 
due to the operation of the car keeps them moving laterally, thus 
overcoming the formation of a cone of metal on the negative contact 
point caused by the small particles transferred from the positive. 



Fig. 226. Bijur Vibrator Voltage Regulator 
Courtesy of “The Horseless Age” 


















































ELECTRICAL EQUIPMENT 


345 


Starting Motor. This is of the series-wound multipolar type. 
1 he installation of motor and starting switch as mounted on Hupp 
cars is shown in Fig. 227. 

Instruments. A dash ammeter is supplied. With constant 
voltage control the amount of current delivered to the battery 
by the generator depends upon the condition of the former. With 
battery almost discharged, its voltage is lowered and the current 
reading may then be as high as 15 to 20 amperes. With battery 
fully charged and no lights on, the reading will decrease to 5 amperes 
or less, the charging current at all times depending upon the state 
of charge of the battery. 



Wiring Diagrams. Winton. This, as shown in Fig. 228, is a 
'single-wire system. The generator is located alongside the trans¬ 
mission case and is belt-driven, provision for belt adjustment being 
made by swinging generator to tighten belt. The numbers on 
the wires indicate the sizes of wire used for connecting the various 
apparatus. Ground connections are on engine and transmission 
case. In this installation the starting switch is mounted directly 
on the starting motor. A spare lamp circuit is provided on which 
a portable, trouble-hunting lamp may be connected. Fuses are 
provided on all lamp circuits. 

Jeffery. Fig. 229 illustrates the six-volt two-wire system used 
on the Chesterfield Six Model. With the exception of the out-of- 


























































































340 ELECTRICAL EQUIPMENT 



Fig. 228. Bijur System as Installed on the Winton 




































































































































ELECTRICAL EQUIPMENT 347 

/ 








































































































































































348 ELECTRICAL EQUIPMENT 

focus lamps in the headlights for city running which are on the 
three-wire plan, one side being grounded, all apparatus is connected 
with two wires. In addition to lamp fuses, the ground connection 
is also fused. The blowing of any of these fuses does not affect 
the ignition circuits. The generator is mounted on the right side 
of the motor and is driven through a flexible coupling from the 
timing-gear shaft. At its rear end, the generator is connected 
through a jaw coupling to the water pump, this shaft also serving 
to drive the magneto. The starting switch is mounted on a housing 
covering the motor pinion, the starting motor being mounted on 
the left side of the engine. A five-way switch provides lamp 
control. 

Ilnpp. Fig. 230 shows the 6-volt single-wire system. This 
diagram is simplified by the omission of the magneto, current from 
the battery being supplied to a single coil and distributor system 
for this purpose. The generator is bolted to an extension on the 
right side forward of the engine and is driven by silent chain from 
the crankshaft. The generator is of the third-brush regulation type. 
The field windings are protected by a 12-ampere fuse. There is a 
four-way switch for lighting circuits. 

Apperson. The 6-volt two-wire system is shown in Fig. 231. 
The generator is of the third-brush regulation type. A “charge 
indicator” is fitted instead of an ammeter, having three readings— 
charge, floating, and discharge. Floating is the neutral position 
and the indicator should show this when the engine is stopped and 
no lights are on, and may show either charge or floating at car 
speeds in excess of 12 miles per hour with lights on, according to 
the condition of the battery. Generator fields are protected by a 
12-ampere fuse. 

Scripps-Booth. In this connection is used the 12-volt single¬ 
wire system employing a single unit or dynamotor for charging 
and starting. The dynamotor is driven by silent chain from the 
crankshaft. At speeds above 10 miles per hour, it acts as a 
generator to charge the battery; at speeds below this point, it 
automatically acts as a motor to drive the engine. Control is by 
three-way switch, having on, off, and idle positions.* In the on 
position, the dynamotor is connected to the battery, the generator 


* Earlier models like Fig. 232 used a two-way switch. 



ELECTRICAL EQUIPMENT 


349 


field circuit is closed, and the ignition circuit is closed. This is 
the normal operating position. In the off position, all circuits 
are opened and the car cannot be run. Shifting the switch to the 



idle position closes the ignition circuit so that the engine can be 
operated, but the dynamotor is disconnected from the battery 
and its field circuit is opened so that it generates no current. 


Fig. 230. Wiring Diagram for the Bijur System on the Hupmobile 





























































































350 


ELECTRICAL EQUIPMENT 


Fig. 232 shows the wiring diagram as used on the earlier models of 
the Scripps-Booth, while Fig. 233 is the diagram of later models 



of the same make. A current indicator shows the operation of 
the system and a four-way lighting switch is employed. The gen- 


Fig. 231. Wiring Diagram for the Bijur System on the Apperson Car 














































































































ELECTRICAL EQUIPMENT 


351 


erator produces current at 12 volts and charges the storage 
battery cells in series. Fourteen-volt tungsten lamps are used. 


I 



Instructions. Winton, No charge reading will be indicated on 
the ammeter when the engine is running (on high gear or direct 


Fig. 232. Bijur System as Installed on Earlier Models of Scripps-Booth Cars 























































































352 ELECTRICAL EQUIPMENT 



Fig. 233. Bijur System as Installed on Later Models of Scripps-Booth Cara 

































































































ELECTRICAL EQUIPMENT 


353 


drive) at a car speed of less than 10 miles per hour. Failure to indi¬ 
cate a charge at speeds higher than this is a sign that the generator 
belt is too loose or that the generator itself is inoperative. To 
determine this, remove No. 10 black wire, Fig. 232, connected to 
No. 6 post on the terminal block, which goes into the aluminum box 
above it. Connect a voltmeter between this wire and the chassis 
and run the engine at a speed corresponding to a travel of 15 miles 
per hour on high gear. The voltmeter should indicate 7.3 to 7.4 
volts. Instructions regarding brushes, commutator, and tests of 
armature- and field-winding circuits with the aid of testing lamp as 
given in connection with the Auto-Lite system apply to determine 
the nature of the fault in the generator. A special disconnecting 
plug is incorporated in the regulator box on top of the generator. 
This plug has two fiat parallel faces and should never rest in its 
receptacle so that these fiat faces stand in a vertical position, but 
should be pushed in and turned in either direction past its central 
position until it locks. When making tests for generator faults see 
that this plug is in the proper position to close the generator circuit. 

To remove the regulator box from the generator, the discon¬ 
necting plug should be pushed in and turned to its central position 
wLen the plug may be withdrawn from its socket. After removing 
the plug, the knurled screw on top of the regulator box should be 
loosened and the box lifted by grasping it and the plug receptacle 
at the same time. Do not hammer the receptacle in order to release 
the box. If the disconnecting plug is round and knurled on the 
portion extending from the receptacle, the plug may be withdrawn 
when the V-groove extending horizontally on the plug matches with 
the slot at the top of the receptacle. The plug should never be left 
in this position, but should be turned in either direction until it 
springs forward and locks. Every five hundred miles, this discon¬ 
necting plug should be pushed inwardly to unlock it, and turned past 
its vertical position until it springs forward and locks. In carrying 
out any repairs or tests involving the disconnection of any of the 
wires which might cause a short circuit by coming in contact with 
metal parts of the car, the cable connected to the positive terminal 
of the battery should be disconnected and its bare end taped. This 
naturally applies to all grounded electrical systems and not merely 
to the car under consideration. 


354 


ELECTRICAL EQUIPMENT 


Jeffery {Chesterfield Six). Instructions for failure of generator, 
starting motor, lamp circuits, etc., are the same as those given in 
connection with other installations, except that in making tests the 
fact that two-wire circuits are employed must be borne in mind and 
connections made accordingly. The headlights supplied are special 
double-filament lamps, one of the filaments being out of focus to 
provide a non-glaring light for city driving. Where emergency 
replacements are made with standard single-filament lamps (double¬ 
contact type), the lamp controller should be turned to the in focus 
bright position when the head lamps are to be used. It is not possi¬ 
ble to dim the lights under these conditions. In making a head¬ 
lamp double-filament bulb replacement, the lamp controller should 
be turned to the out of focus dim position. The new bulb should 
then be inserted in its socket. The out-of-focus filament in each 
headlight should then burn dimly. If they do not, the last bulb 
inserted in its socket should be removed, reversed, and replaced. 
When bulbs are correctly inserted, the two out-of-focus filaments 
will burn dimly when the lamp controller is turned to the out of 
focus dim position. Instructions for the use of the disconnecting 
plug are the same as for the Winton. 

To determine whether generator is inoperative remove wire 
leading from the ammeter to No. 5 post of the junction and fuse 
block, Fig. 229, then connect voltmeter to terminals 2 and 5 and run 
engine as previously directed. A fuse is in the ground circuit be¬ 
tween the magneto tap and the lamp controller and this fuse will 
blow if an accidental ground is made on either side of the system. 
The blowing of this fuse when the lamp controller is in the off posi¬ 
tion, shows that the accidental ground causing it is on the positive 
side of the system. Should the ground fuse blow when the lamp 
controller is in the all bright or out of focus bright positions, it shows 
that the accidental ground is on the negative side of the system. 
In testing the wiring to locate grounds, the headlight bulbs should 
be removed and the ground wire leading to connecting post No. 7 
of the fuse and terminal block should be disconnected, and the 
magneto switch should be placed in the running position. With 
the ground fuse blown, the following lighting conditions obtain. 
Controller at in focus bright position, lamps will burn normally. At 
out of focus bright position lamps will not light; at all bright position 


ELECTRICAL EQUIPMENT 


355 


only the in-focus filaments will light. At the out of focus dim position 
all the lamps will light. 

Hupp. General instructions covering failure of generator, 
starter, or lamp circuits apply as already given. Many other impor¬ 
tant factors might be mentioned such as open circuit, loose connections, 
blown generator fuse, corroded battery terminal, and brushes not 
seated properly. If the starting motor is damaged so that its removal 
is necessary, it should be removed by disconnecting one of the battery 
terminals and the two small wires B and C as shown on.the diagram, 
Eig. 230. Next remove heavy cables A and D from the starting 
motor. The holding nuts on the motor can then be loosened to permit 
its removal. In replacing a starting motor, the pinion riding on the 
square shaft of the motor should be tested to see that it has a free 
sliding fit on the shaft. Do not use a file but see that all surfaces are 
perfectly clean and well oiled. The pinion must be guided over the 
shaft before the motor is pushed into place. Connect the new motor 
in accordance with the wiring diagram. Do not make storage-battery 
connections until all other connections have been made and while 
repairs are being carried out battery terminals should be protected. 

In case an inoperative starting motor is removed and a new one 
is not immediately available for installation, the car may be run 
with the hand-starting crank by proceeding as follows: Terminals 
on the end of cable A and the wires B and C must be connected 
together by binding tightly with bare copper wire and then thor¬ 
oughly taping so as to form a good electrical joint that is well insu¬ 
lated. Secure the cables and wires to adjacent parts of the car with 
the aid of cord or insulating tape (not with wire) so that they cannot 
be chafed or otherwise injured by moving about while the car is 
running. The heavy cable D must be similarly taped and secured. 
The lighting system is then independent of the starting system. 
By making a study of the wiring diagram and carefully noting 
the different circuits, the starting circuit may be isolated from the 
lighting circuits on any car having a two-unit system. Before 
replacing a blown fuse always examine for grounds, short-circuits, 
or defective bulbs. Never replace a blown fuse with anything 
but another of the same capacity. If it is necessary to use the 
car before the trouble can be located, the grounded circuit can be 
left open by omitting its fuse. When all lights fail this is due to an 


• 356 


ELECTRICAL EQUIPMENT 


open circuit between the battery and the fuse block. Examine 
the battery connections carefully and also connections of the cable A 
and wire C when they are connected to the starting motor; also 
examine the connections E at the ignition switch, F at the lighting 
switch, and the fuse block. If all of these connections are clean and 
tight, making good electrical contact, there is a broken wire between 
these points and the various circuits should be tried with the testing 
lamp. 

Before making the usual tests for an inoperative generator 
see that the fuse protecting the field windings is intact. If this 
fuse has not blown and all connections are tight and properly made, 
remove wire from B which connects the generator to one terminal 
of the starting motor, and connect an ammeter in this circuit. 
Run the engine at a good speed, equivalent to 15 miles per hour 
or more. If the ammeter shows no current, while the commutator 
is bright, brushes bearing on it properly, and the battery connections 
are all right, test the armature and field windings with a lamp 
outfit to locate short-circuited windings. Do not remove the gen¬ 
erator unless another is available for immediate installation. If 
it is necessary to run the car with the generator inoperative, the 
field fuse should be removed as a precaution against damage. To 
take the generator off, remove the circular cover plate from the 
front end of the chain case and take out the three bolts holding 
the generator to the rear side of the chain case. The driving chain 
should be supported through the opening at the front to prevent 
it from falling to the bottom of the chain case. It is not necessary 
to remove a pin connecting the links together. The chain may 
be tightened by loosening the three bolts mentioned and swinging 
the generator outward until the slack is taken up and then retight¬ 
ening the bolts. 

Apperson. The generator on the Apperson system has a fuse 
protecting the field circuit. Fig. 231. Open connections between the 
generator and the battery will blow this fuse. It is located on the 
end of the generator adjacent to the terminals and is protected 
by an aluminum housing. To examine, remove the latter by taking 
out its two holding screws. The fuse is of the standard glass-tube 
type and may be lifted out of its clips with the thumb and finger. 
Do not attempt to pry a fuse out of its clips with a screwdriver 


ELECTRICAL EQUIPMENT 


357 


or other tool. Before replacing a blown fuse examine all connections 
and wiring to see that they are in good condition. The engine 
must never be run with the battery disconnected, as this will blow 
the generator-field fuse. These instructions apply to all generators 
equipped with field fuses, although the placing of the latter will 
naturally differ in other systems. Ipstructions for testing circuits 
are the same as those for other two-wire systems. There are no 
grounds except in the ignition system. Tests for inoperative 
generator or starting motor and instructions for the removal of either 
of these units are the same as already given. 

Scripys-Booth. With the higher voltage battery supplied 
(12-volt) in the single-unit system employed on this car, the cells 
are of considerably smaller capacity (35’ampere-hour as compared 
with 80-ampere-hour on the Apperson and 120-ampere-hour on 
the Winton), so that if the car has been left standing for long periods 
with the lamps on, or is only run for short periods during the day¬ 
time, thus giving the battery no opportunity to become fully charged, 
it will not have sufficient capacity to start the engine. As the motor- 
generator (dynamotor) automatically reverses its functions in 
accordance with the speed at which it is being driven by the engine, 
the latter should not be run with the switch in the on position at 
speeds corresponding to a travel of less than 10 miles per hour. Lffider 
such conditions, as when the car is left standing with the motor 
idling slowly, or when driving at a very slow pace as in congested 
traffic, the switch should be placed at the idle position. Should 
the engine stall when the switch is at the idle position, it should 
be shifted immediately to the on position. For failure of the current 
indicator to work see instructions on this point on page 353. 
The indicator should never show discharge when the car is running 
above 12 miles per hour. 

If necessity requires the operation of the car with the battery 
disconnected, disconnect the wires from the generator at the 
machine, as otherwise it is liable to injury. On the earlier Scripps- 
Booth models. Fig. 232, the engine should not be used as a brake in 
running down hill except in emergencies, but on later models. Fig. 
233, this may be done without injury to the dynamotor by 
throwing the switch to the off position. By referring to the wiring 
diagram it will be noted that the shroud-lamp and cowl-lamp bulbs 


358 


ELECTRICAL EQUIPMENT 


\ 


are of the double-contact type; all others are of the single-contact 
type. All must be 14-volt lamps, 15 c.p. and 4 c.p. in the headlights 
and 2 c.p. for the others. 

Packard. Fig. 234 is the wiring diagram of the Packard twelve- 
cylinder motor, showing all connections for the ignition, starting, and 
lighting. Beginning at the left, are the double headlights and their 
connections, just back of them, the twelve-cylinder distributor and its 
connections to the twelve spark plugs, in groups of six. This dis¬ 
tributor is illustrated in the preceding ignition section. It is prac¬ 
tically two six-cylinder distributor units, each of which has its own 
induction coil, though both naturally must run synchronously, i.e., 
they are timed together, as the ignition alternates from one group of 
cylinders to the other. The secondary cables are represented. by 
double lines which are shown part solid and part open, to distinguish 
them from other wires. To the right of the two coils, in the lower 
central part of the diagram, is the junction box, incorporating all the 
lighting-circuit fuses. Further to the right of this, the “switchboard” 
is a unit mounted at the head of the steering column of the car and 
which brings to one convenient point within easy reach, all the light¬ 
ing as well as the ignition switches. 

To indicate the heavy cables of the starting circuit, a double line 
is used with cross lines at short intervals. Two-wire connections are 
used throughout the entire system, barring the ignition. On the 
motor the high- and low-tension wiring is readily distinguishable by 
the difference in size, the low-tension wires having the thinner insu¬ 
lation. The low-tension current is carried in a complete two-wire 
circuit not grounded at any point. The high-tension current is 
grounded from the spark-plug body, through the motor to the coil 
bracket. The starting circuit may readily be traced by its heavy 
connections, and it will be noted that it is the shortest and most 
direct circuit in the system. Referring to the junction box, the 
strap shown connecting posts A and B is used in this way in all 
states the laws of which allow direct control of the tail light from the 
driver’s seat. With this arrangement, the dash and tail lamps are 
in parallel and both are protected by the tail-lamp circuit fuse. 
For states requiring an independent tail-lamp circuit, such as 
Illinois, this strap is connected across posts B and C; with this 
arrangement, the dome-light fuse protects the tail light, while the 



Fig. 234. Wiring Diagram of Bijur System for Packard “Twelves’ 






















































































































































































































































360 


ELECTRICAL EQUIPMENT 


tail-light fuse protects the dash light. All wires are run in conduits, 
the various circuits enclosed in each conduit being indicated at dif¬ 
ferent points on the diagram. High-tension wires from distributors 
to spark plugs are carried in tubes supported on the cylinder blocks. 

BOSCH=RUSHMORE SYSTEM 
Twelve=Volt; Two=Unit; Single=Wire 

Generator. The bipolar shunt-wound type of generator is 
made in two sizes, one for driving from pump shaft, and the other 
for silent-chain or belt drive. 

Regulation. Ballast Coil Employed. The regulation is the 
inherent type, using a bucking-coil winding in conjunction with a 
so-called “ballast coil” which automatically cuts the bucking coil 
in or out of the circuit, according to the resistance of the ballast 
coil. Mention has been made in Elementary Electrical Principles, 
Part I, that the resistance of certain metals increases greatly with an 
increase in their temperature. This is particularly the case with iron, 
and advantage has been taken of this fact in the Bosch-Rushmore 
generator. The ballast coil consists of a few turns of fine iron 
wire on a fluted porcelain rod. The bucking coil, which is simply a 
reversed field winding, has a polarity opposite to that of the winding 
employed to excite the field magnets. Consequently, when a current 
passes through it, the effect is to oppose the excitation of the field 
magnets. The bucking coil is connected as a shunt across the iron 
ballast coil. Fig. 148. The resistance of the bucking coil is consider¬ 
ably greater than that of the ballast coil when the iron wire is cold or 
only warm, so that at low engine speeds practically all the current 
generated passes through the shunt winding of the dynamo. How¬ 
ever, the resistance of the wire increases at a constant rate with the 
current up to 10 amperes, after which it increases very suddenly owing 
to the heating effect of the current in the iron. Any current in excess 
of 10 amperes accordingly must pass through the bucking coil, which 
consequently tends to limit the output of the generator to that amount 
of current. 

Starting Motor. Method of Operation. This is the series- 
wound bipolar type, as illustrated in section. Fig. 155, which 
shows the field windings as cut in half. As the illustration is to scale, 
the large size of the conductors in a series-wound field will be noted, 


ELECTRICAL EQUIPMENT 


361 


this being necessary owing to the heavy current required to operate 
a starting motor. The starter pinion is mounted directly on the 
armature shaft without any intermediate gearing and the engagement 
of this pinion with the flywheel gear is automatic, as will be made 
clear by referring to Fig. 155, and to Fig. 165, showing the mounting 
of the Bosch starter on an automobile motor. 

Refer back for a moment to the description of magnetic fields 
under Electrical Principles, Part 1. See also the description of the 
action of a solenoid. • It will be noted that every magnet has a 
magnetic circuit and that the lines of force comprising it are most 
numerous in close proximity to the poles of the magnet. In other 
words, the magnetic attraction is most intense at those points. The 
magnetic poles of the field of the Bosch starter are the metal projections 
each of which is held in place by two machine screws, top and bottom, 
as will be seen in the sectional view. It will also be plain that the 
armature of the starting motor is not directly in the magnetic field 
of these poles, and that it is held in this off-center position by the 
spring pressing against its shaft as seen at the left. The moment 
the switch is closed, however, and the field magnets are excited, 
the whole motor acts as a solenoid and forcibly pulls its armature 
into a central position against the spring, at the same time as it 
begins to revolve. This gives ideal conditions for meshing the 
starter pinion with the flywheel gear, as it is pulled against the 
latter and at the same time revolved, so that the moment its teeth 
correspond with spaces in the flywheel gear, it slips into engagement 
and begins to turn the engine over. As soon as the current is cut 
off by opening the switch, the spring returns the armature to its 
normal inoperative position and disengages the gears. 

Starting Switch. There are two contacts on the starting switch, 
the first sending only a small amount of current through the starting 
motor, this being just sufficient to pull the armature into center 
and engage the gears, when a further movement of the switch sends 
the full current from the battery through the starting motor. This 
progressive movement of the switch and the two circuits between 
the battery and starting motor are shown in Figs. 235 and 236. 
It will be noted that the first movement of the switch throws the 
field of the starter in shunt with its armature, thus causing it to 
revolve slowly, while the further movement of the switch places 


3G2 


ELECTRICAL EQUIPMENT 


the field in series. Fig. 237 shows the actual wiring diagram of the 
starting-motor circuit. In actual operation, the movement of the 

.. — — 



Fig. 235. Wiring Diagram for First Part of Downward Movement 

of Bosch Switch Pedal 


switch is practically instantaneous. No damage will result in case 
the switch is held down after the engine starts, as the moment the 
latter begins to fire, the load on the starting motor is greatly reduced 
and the current consumption decreases to a point where the field 
coils no longer have sufficient pull to overcome the spring on the 
armature. The pinion on the shaft of the latter is automatically 
disengaged from the ffywheel gear and the motor will only idle 
slowly, owing to the armature being off center. 

Instruments and Protective Devices. A standard double-reading 
ammeter is si^pplied. The normal charging rate is approximately 
20 amperes with the car running 20 to 25 miles an hour or over. 

In addition to the usual battery cut-out which is an essential 
feature of most electric lighting and starting systems and will be 
found on most cars so equipped, whether it is specifically mentioned 
in the description of the various systems or not, a ballast coil is 
inserted in the charging circuit. This is similar to the ballast coil 
used in the regulation of the generator. This ballast coil is controlled 





Fig. 236. Wiring Diagram for Circuit When Switch Pedal Has Completed 

Downward Movement 


by the left-hand button of the switch (installation on Mercer cars), 
and its function is to prevent overcharging of the ])attery. By 



























ELECTRICAL EQUIPMENT 363 



Fig. 237. Wiring Diagram for Bosch-Rushmore Starting System on a Mercer Car 



































































































364 


ELECTRICAL EQUIPMENT 


putting it in the circuit the charging rate is reduced to 5 amperes. 
Where a great amount of day running is done, it is recommended 
that the ballast coil be left in circuit. All circuits, except starting 
motor, but including field coil of generator, are fused. 

Wiring Diagram. The various circuits of the single-wire system, 
as employed in the Mercer installation, are shown in Fig. 237. The 
automatic cut-out for the battery circuit is mounted on the generator. 
Ground connections are not indicated in every instance, as in the 
case of the generator and the starter they are made within the 
apparatus itself, and this is also the case with the lamps, which are 
known as the single-contact type. The latter are employed in all 
single-wire systems. In this case, they must be 12-volt bulbs as six 
cells of battery are employed. In making lamp replacements, only 
bulbs of the proper type, i.e., single or double contact, depending 
on whether the system is one- or two-wire, and of the proper voltage 
must be used. This, of course, applies to all electric systems, as, 
where a 6-volt bulb is placed on a 12-volt system, it will be burned 
out immediately. A 12-volt bulb on a 6-volt circuit will burn very 
dimly, so that when only one headlight burns brightly the voltage 
of the dim burning bulb should be ascertained before looking for 
trouble elsewhere. If the manufacturer’s label has disappeared 
from the bulb, it can be tested with dry cells, starting with four in 
series which should make a 6-volt bulb burn brightly, and increasing 
to eight in series for a 12-volt bulb. 

Instructions. Battery Charging. With all lamps on, the 
lighting equipment consumes about 12 amperes; the side and tail 
lamps together take about 3 amperes, so that when the ammeter 
reading shows a consumption in excess of these figures for the condi¬ 
tions given, the usual tests should be made for short circuits or 
grounds. The latter will be the case also when the ammeter shows 
any discharge reading with all lamps off. Any discharge under 
such conditions is leakage. However small it may be, it should be 
investigated at once, as it will run the battery down. The trouble 
may consist of a short circuit in one of the lighting circuits or it may 
be due to current flowing back through the generator caused by the 
failure of the cut-out to work properly. In case the lamps burn 
dimly when the generator is at rest, it indicates that the charging 
rate is not sufficient to keep the battery up. This may be caused 


ELECTRICAL EQUIPMENT 


365 


by a great deal of night running with the ballast coil in the charging 
circuit, as the charging rate is then only about 5 amperes. In the 
majority of instances, however, it will be found, probably, that 
the battery itself is responsible. For instructions on battery main¬ 
tenance, see end of this article. 

The battery furnished on the Mercer has a capacity of 120 
ampere-hours. The starting motor takes approximately 200 amperes 
for its operation which, with the engine in good condition, should 
not consume more than 10 seconds for each start. To replenish the 
current consumed by starting twelve times in a day, or say a total 
of two minutes’ operation of the starting motor at the 200-ampere 
rate, the engine would have to run only about half an hour at the 
average charging rate of 15 amperes. With the current consumed 
by the lamps, based upon their use for 5 hours per night, plus the 
natural deterioration losses of the battery, drop in efficiency through 
switches, contacts, and wiring, approximately two hours of daylight 
running would be required to keep the battery fully charged. Night 
running can be disregarded where battery charging is concerned, 
as the total consumption of the lamps is practically the equivalent 
of the average charging rate. An undue brilliancy of the lamps 
would indicate a battery wire off or loose and should be 
investigated. 

Fuses. When ammeter shows no reading of charging current 
with the engine running, the most likely place to look for the trouble 
is the fuse protecting the generator field circuit. (This applies to 
all generators so equipped.) The field fuse of the Bosch-Rushmore 
generator is located on the distributing board, and it may be tested 
by short-circuiting the ends of the fuse cartridge with a pair of pliers, 
a screw driver, or other piece of metal. In case the ammeter then 
registers a charging current, the fuse has been blown out and should 
be replaced with another of the same type and capacity. As all 
circuits, except the starting motor, are fused, a similar test can be 
carried out in case of the failure of any of them. The blowing of a 
fuse is usually due to a short circuit, and before replacing it, the 
reading on the ammeter should be noted when the fuse terminals 
are short-circuited with the pliers, the generator being idle. A 
short circuit will be indicated by the needle of the ammeter moving 
sharply to the limit of its travel on the scale. The use of the testing 


ELECTRICAL EQUIPMENT 


3GG 


lamp for finding short circuits is given in connection with the instruc¬ 
tions under Auto-Lite, Delco, Gray & Davis, and other systems. 

Gear Meshing. Faliure of the starting motor to operate will be 
due to an exhausted battery in the majority of instances, but on 
cars that have seen considerable service, it may be caused by a 
settling or distortion of the frame resulting in binding of the gear 
teeth too tightly. This may be corrected by readjusting the mounting 
of the starting motor in its supporting cradle so that the gears mesh 
quite loosely. It should always be possible to push the gears into 
mesh by hand without any effort. Unusually slow operation of the 
starting switch may also cause failure of the starting motor to 
operate properly. The first contact of the switch places a small 
resistance in the circuit and too long a delay may overheat this 
resistance to such an extent as to burn it out. Over-rapid operation 
of the switch may also cause failure to start as the gears are not 
allowed to mesh-. This will be indicated by their clashing and by 
the spinning of the starting motor. The switch should be given a 
comparatively slow but steady movement from first to second contact. 




i 


WAGNER GENERATOR AND STARTING MOTOR AS DESIGNED FOR SCRIPPS-BOOTH CARS 

Courtesy of Wayner Electric and Manufacturing Company, St. Louis, Missouri 









ELECTRICAL EQUIPMENT FOR 

GASOLINE CARS 

TART V 


ELECTRIC STARTING AND LIGHTING 

S Y STEMS —(Continued) 

PRACTICAL ANALYSIS OF TYPES— (Continued) 

DELCO SYSTEM 

Six=Volt; Single=Unit; Single=Wire 

Dynamotor. The dynamotor is usually referred to as a motor- 
generator, though it is actually a generator-motor, i.e., a dynamo- 
motor which has been shortened to dynamotor. This term has been 
adopted by the Society of Automobile Engineers to designate the 
combination unit in question. A motor-generator as employed for 
transforming alternating current to direct current consists of two 
separate units: a motor driven by alternating current and a dynamo 
generating direct current, mounted on the same bed, and with their 
armature shafts directly coupled. 

The Delco single-unit machine consists of two separate field 
windings and two independent armature fundings, the latter being 
connected to separate commutators at either end of the shaft. In 
combination with this is an ignition timer and distributor mounted 
at the generator end and driven from the armature shaft through 
spiral gears. The generator is driven from the pump shaft of the 
engine through an over-running clutch which permits the armature 
to run free when the unit is operating as a starting motor. At the 
starter end, the armature shaft carries a small pinion meshing with 
the larger unit of a pair of sliding gears, the smaller of which is 
adapted to slide into engagement with the gear ring of the flywheel. 
This arrangement is shown clearly in Fig. 238; it provides a double 
gear reduction between the starting motor and the engine. In the 




ELECTRICAL EQUIPMENT' 


3()8 

smaller of the two sliding gears is incorporated an over-running 
clutch which releases the starting motor from the engine in case the 
latter should be speeded up without disengaging the starting gears, 
thus preventing damage to the starting motor by running it at an 
excessive speed. 

Control. The necessary switches for putting the generator in 
circuit to charge the battery, and to cut it out of this circuit and put 
the starting motor in circuit with the battery to turn the engine 
over, are built into the machine and take the form of lifting brushes. 
Their operation is as follows: 

To start, the ignition button on the switch panel on the dash is 
first pulled out. This connects the storage battery with the ignition 



circuit and with the armature of the dynamotor through a resistance 
which permits only a current of small value to pass. This current 
motorizes the generator and causes its armature to rotate slowly, 
giving it just enough speed to facilitate the meshing of the starting 
gears. The starting pedal is then depressed and during the first 
part of its travel it serves to engage the gears. Fig. 238. Then it 
withdraws the pin P, Fig. 239, allowing the motor brush switch to 
make contact with the motor commutator. At the same time it 
causes the generator switch to open, thus cutting out the generator 
during the cranking operation. As soon as the motor brush makes 
contact, the full current from the battery passes through the series- 




















































































































ELECTRICAL EQUIPMENT 


360 


field winding of the motor element and through the corresponding 
armature windings, and sets the armature rotating at full speed. 



The starter pedal is returned to the open position by a spring 
and as soon as it is released, the motor brush is lifted from its com- 


Fig. 239. Details of Brushes and Brush Switches, Delco Single-Unit Sy.stem 



























































370 


ELECTRICAL EQUIPMENT 


mutator and the generator switcli is closed, thus cutting out the 
motor windings and connecting the unit to the storage battery as a 
generator. Charging begins when the engine reaches a speed 

corresponding to 7 miles per hour. 

Regulation. Constant-Voltage 
Control Type. Of the four types pro¬ 
duced the first employs a resistance 
variable in accordance with the speed. 
The regulator consists of a solenoid 
the core of which has a spool of 
resistance wire wound on its lower 
end, Fig. 240. This core or plunger C 
floats in a bath of mercury, and, in 
accordance with the depth to which 
it sinks in the mercury, more or less 
of the resistance wire is short-cir¬ 
cuited by the mercury. The solenoid 
^ winding A is connected in shunt 
across the generator terminals so the 
current flowing through it and the 
magnetic effect exerted by it are 
always proportional to the voltage 
at the generator terminals. The 
resistance wire on the plunger of the 
solenoid is in series with the shunt- 
field winding of the generator. If 
there were no other forces than the 
buoyancy of the mercury and that 
of gravity acting upon the plunger it 
would remain at approximately the 
same height, but as the plunger is 
iron it is acted upon by the solenoid 
winding, the effect being to withdraw 
it from the mercury as the current 
through the winding of the solenoid 
increases, thus putting more and more of the turns of resistance 
wire on the spool in circuit. Hence, the greater the current flowing 
through the solenoid the greater will be the resistance in circuit with 



iiiiiiiiiiiiii. 


Fig. 240. Section Showing Delco 
Mercury-Bath Voltage Regulator 






























































































ELECTRICAL EQUIPMENT 


371 


the shunt-field winding of the generator. To overcome the effect of 
temperature variation on its operation which would cause the charging 
rate to be higher than intended at high temperatures, and vice versa, the 
solenoid is wound and connected in series with a resistance wire of 
special material having a negative temperature coefficient (i.e., whose 
electrical resistance decreases with an increase in temperature), so 
that the total resistance of the solenoid circuit remains the same 
regardless of temperature changes. With a few exceptions, such as 
the Olds 1915 Model 55, this method of voltage regulation is not 
employed on cars subsequent to 1914. 

BucJdng-Coil Type. This is the type of regulation usually 
referred to as inherent in that it is accomplished by the windings of 
the generator itself. The latter is compound wound but the series 
field has a reversed polarity, so that its effect is to oppose that of 
the shunt winding. 

Mechanically Varied Resistance. In this type the same prin¬ 
ciple as that employed in the first type described is used, i.e., that 
of weakening the generator field by increasing the amount of resist¬ 
ance in circuit with it in accordance with the speed, except that it is 
varied by mechanical means instead of electrical. The regulator 
resistance is in the form of a rheostat, the arm of which is controlled 
by a centrifugal governor driven from the shaft of the ignition dis¬ 
tributor. As the weighted element of the governor expands under 
the influence of the increasing speed, it moves the arm of the rheostat 
over the contacts each of which represents an added resistance to 
the circuit. 

Both the bucking-coil type and the mechanically varied type of 
regulation are employed in Delco systems installed on 1915 and 
subsequent cars, different models of the same make and the same 
year having different systems, so that instructions for their main¬ 
tenance depend upon the system employed. 

Third-Brush Method. As the voltage generated varies directly 
with the speed, it is evident that to maintain a nearly constant 
voltage with a variable speed, it becomes necessary to decrease the 
magnetic field as the speed increases. Since the magnetic field of 
the generator is produced by the current in the shunt-field winding, 
a decrease in this current as the speed increases will regulate the 
output. Bearing in mind that a current always produces a mag- 


372 


ELECTRICAL EQUIPMENT 


Shunt Field Winding which produces 
the Magnetic Field 


netic field, whether the latter is desired or not, the theory of this 
method of regulation will be clear from the following reference to 
Fig. 241. The full voltage of the generator is obtained from the 
brushes C and B, When the magnetic field from the pole pieces 
iV and S is not disturbed by any other influence, each coil is gener¬ 
ating uniformly as it passes under the pole pieces; the voltage from 
one commutator bar to the next is practically uniform all around 
the commutator. Therefore, the voltage from brush C to brush E 
is about 5 volts, when the total voltage between the main brushes 
C and Z) is 6i volts and current at 5 volts’ pressure is supplied to the 

shunt-field winding. This 
voltage is sufficient to 
cause approximately IJ 
amperes to ffow through 
that winding. 

As the speed in¬ 
creases, the voltage does 
likewise, charging the 
battery. This charging 
current flows through the 
armature winding caus¬ 
ing a magnetic effect in 
the direction of the arrow 
B and the latter acts 
upon the main magnetic 
field, which is in the 
direction of A, with the 
result that the latter is twisted or distorted out of its original 
position, in much the same manner as two streams of water meet¬ 
ing are deflected from their original directions. This deflection 
causes the magnetic field to be strong at the pole tips G and F, and 
weak at the opposite tips, with the result that the coils generate a 
very low voltage while passing from brush C to brush E (the coils 
at this time are under the pole tips having a weak field) and produce 
the greater part of their voltage while passing from brush E to 
brush D, The amount of this variation depends upon the speed at 
which the generator is driven, thus decreasing the current supplied 
to the shunt field as the speed increases. 



// 















ELECTRICAL EQUIPMENT 


373 


Protective Devices. Battery Cut-Out. In connection with 
Delco systems using the voltage regulator of the mercury type 
already described, a battery cut-out or a cut-out relay, as it is some¬ 
times termed, is emplo^^ed. Fig. 242 shows this cut-out together 
with a diagram of its windings. It consists essentially of a com¬ 
pound-wound electromagnet and a set -of contacts designed to be 
closed by the movement of the pivoted armature of the magnet, 
and to be opened by a spring when the magnet is not excited. The 
compound winding consists of a voltage coil of a great many turns 




Fig. 242. Sketch and Diagram for Delco Cut-Out Relay 

of fine wire, as shown at the left of the wiring diagram, and a current 
coil of a comparatively few turns of heavier wire. As soon as the 
engine begins to drive the generator the voltage of the latter “builds 
up’^ and when it reaches a value between 6J and 7f volts, the current 
passes through the voltage winding of the electromagnet and pro¬ 
duces sufficient magnetism to overcome the tension of the spring B, 
attracting the armature C to the core D which closes the contacts 
at A. These contacts close the circuit between the generator and 
the storage battery and the whole output of the generator then flows 







































374 


ELECTRICAL EQUIPMENT 


through the current coil, greatly increasing the magnetism in the 
core in the same direction thus strengthening the pull on the arma¬ 
ture C and holding the contacts tightly closed. When the generator 
slows down and the voltage drops below that of the battery, current 
flows from the latter to the generator through the current coil in 
the reverse direction. But, as the voltage coil is directly in circuit 
with the generator, the flow of current through it continues in the 
same direction, so that the magnetizing effect of the battery current 
through the current coil opposes that produced by the voltage coil 
and the latter is not sufficient to hold the armature against the 
spring. This causes the contacts to open and prevents any further 
flow from the battery through the generator. The relay is designed 



CIRCUIT 
BREAKER 


IMMER 
RESISTANCE 


Fig. 243. Delco Combination Switch 

Courtesy of Dayton Electrical Engineering Laboratories Company, Dayton, Ohio 


to cut out the battery before the discharge current reaches a value 
of 1 ampere. As mentioned previously, but few cars subsequent to 
1914 are fitted with systems using the mercury voltage regulator and 
only these systems are equipped with a battery cut-out. 

Circuit Breaker. Delco systems fitted to cars subsequent to 
1914 are protected by a circuit breaker. This takes the place of 
the fuse block and fuses employed in most other systems. It is 
mounted on the combination switch controlling the ignition, gen¬ 
erator, and lights, as shown by Fig. 243. The button M controls the 
magneto ignition circuit, and the button B the dry-battery circuit 
for the same purpose. In addition both these buttons control the 
circuit between the battery and the generator for the purpose of 























ELECTRICAL EQUIPMENT 


375 


motorizing the latter to start. When the circuit is closed bv either 
button M or button B, current flows from the battery to the gen¬ 
erator, when the engine is not running and when it is running at 
speeds below 300 r.p.m., but the amount of current flowing at the 
lowest engine speeds possible is so small as to be negligible. With 
the engine stopped, pulling out the button M sends sufficient current 
through the generator armature to run it slowly as a motor so that 
the gears may be meshed for starting. The amount of current thus 
employed is limited by a resistance unit in series with the shunt 
field of the generator. 

In principle the circuit breaker is the same as an ordinary elec¬ 
tric bell or buzzer, but its winding and the spring controlling its 
armature are such that it comes into action only when a heavy 
current passes through it. It is included in every circuit of the 
electrical system, including the ignition, with the exception of the 
starting-motor circuit, so that all the current used for every purpose 
except starting passes through it. But as long as the lamps, igni¬ 
tion, and horn are consuming the normal amount of current, it is 
not affected. In case any of the wires of these circuits becomes 
grounded, however, a heavy current passes through the circuit 
breaker, thus producing a strong magnetic pull which attracts the 
armature and breaks the circuit. This cuts off the flow of current and 
the spring again closes the contacts, causing the circuit breaker to pass 
an intermittent current by vibrating its armature. A current of 25 
amperes is required to operate the circuit breaker, but once started it 
will continue to vibrate on a current as low as 3 to 5 amperes. 

Wiring Diagrams. The Delco system is applied to such a num¬ 
ber of different makes of cars, frequently varying in detail not only 
with each succeeding year’s models of the same make, but also on 
different models of the same make and same year of production, 
that space would not permit of reproducing them all here. While 
these wiring diagrams differ in detail, they may, however, be divided 
into three general classes based upon the type of regulation used 
with the generator. At least one of each of these classes of wiring 
diagrams is reproduced here and familiarity with them will make 
it easy to trace the wiring of any system of this make. 

Cadillac. Wiring diagram of the 1912 model is given in Fig. 
244. Reference to a model as early as this is made to show the pro= 


ELECTRICAL EQUIPMENT 



Fig. 244. Wiring Diagram for Generator Circuits of Delco Installation on Cadillac 1912 Models 



















































ELECTRICAL EQUIPMENT 


377 


gressive steps represented by each succeeding year; also because 
there are a great many of these cars still in use. Twelve cells of 
battery were employed though the dynamo generated current at 
7 to S volts (nominally a 6-volt system), and as shown by the dia¬ 
gram which illustrates the connections of the generator circuit, the 
battery was divided into four groups of three cells each in series- 
multiple for charging. An ampere-hour meter showed the state of 
charge of the battery and also indicated how much current was 
consumed by the various circuits, including the starting motor. 
Regulation was by means of extra resistance inserted in the field 
circuit of the generator and an automatic battery cut-out was 
employed. The diagram shown in Fig. 244 is applicable to the con¬ 
nections of all the Delco 6—24-volt systems in use, when the machine 



Fig. 245. Wiring Diagram of Starting Motor Circuit for All Delco 6—24-Volt Systems 


is operating as a generator. The heavy lines indicate the main 
charging circuit. Fig. 245 shows the starting motor circuit of all the 
Delco 6—24-volt systems, and it will be noted that the cells of the 
battery are all in series to supply current at 24 volts, group No. 4 
being utilized to supply current to the lamps at 6 volts. 

Fig. 246 shows the wiring diagram of the Cadillac 1914 model. 
This is a straight 6-volt system, the generator being provided with 
the mercury type of voltage regulator previously described and an 
automatic battery cut-out. The starting-motor circuit is controlled 
by an external switch and the lighting circuits are protected by fuses. 
The earlier form of the combination switch controlling the ignition 
and the preliminary motorizing of the generator for starting, is seen 
at the right. The 1914 diagram is essentially the same, the chief 





























378 ELECTRICAL EQUIPMENT 


T 

K< rt 



4h>AA/# 

tWW^ 




tn 

"3 

'a 

o 


05 


u 

cS 


05 

o 

0 

o 


03 

>> 

w 

o 

_o 

"o 

Q 

ii 

a 

03 

(i 

bO 

cS 


bC 

a 


CO 

T}< 

(N 

S 


difference being the 
substitution of the 
motor brush switch 
for the external switch 
controlling the start¬ 
ing motor. The fuses 
were also replaced by 
two circuit breakers, 
one for the main light¬ 
ing circuits and igni¬ 
tion, and the other 
for the auxiliary 
lamps, horn, and the 
gear-changing sole¬ 
noids, the model of 
that vear being 

1/ o 

equipped with an elec¬ 
tric magnetic gear shift 
in the transmission. 

In the 1915 wir¬ 
ing diagram. Fig. 247, 
the method of regulat¬ 
ing the generator has 
been changed to the 

mechanicallV varied 
%/ 

resistance already de¬ 
scribed. One • circuit 
breaker protects all 
fuses and a rotarv 

t/ 

form of combination 
switch controls all the 
circuits. 

Bnick. Two dif- 
erent types are em¬ 
ployed on the 1915 
models, the only dis¬ 
tinction, however, 
being in the method of 



































ELECTRICAL EQUIPMENT 379 



Fig. 247. Wiring Diagram for Delco System on Cadillac 1915 Models 




















































































































































ELECTRICAL EQUIPMENT 


381 



Fig. 249. Wiring Diagram for Delco Installation on Buick Models C36 and C37 































































































Fig. 250. Wiring Diagram for Delco Installations on Buick 1916 Models 


















































ELECTRICAL EQUIPMENT 


383 


generator regulation. That of Models C24 and C25 is by means of 
the reversed series-field winding or bucking coil, while that of Models 
C36 and C37 utilizes the mechanically varied resistance or rheostat 
operated by a centrifugal governor, as shown in Fig. 249. The buttons 
M and B, in each instance, control the ignition circuit, depending 
upon whether the storage or the dry battery is called upon for the 
ignition current as well as for the current to motorize the generator 
preliminary to starting. The remaining three buttons of the com¬ 
bination switch control the lights and dimming resistance and it will 
be noted that the circuit-breaker forms a part of every one of the 
circuits except that of the starting motor. 

On the 1916 Buick models, the generator is regulated by the 
third-brush method; the brush switches are operated by the starting 
pedal; only the lighting circuits are protected by the circuit-breaker, 
and an ammeter is inserted in the circuit with the latter. Fig. 250. 
No mention is made of the details of any of the ignition circuits in 
these diagrams as that is taken up in the section on Ignition. Apart 
from the fact that the Oakland Model 50 has a 4-pole motor winding 
instead of the bipolar type shown in all the previous diagrams, the 
wiring diagrams of the Oakland models for 1916 are the same as 
those shown for the Buick. On the two 1915 models of the Cole, 
the distinction between the wiring diagrams is the same as that 
mentioned for the two classes of Buick models of the same year, 
i.e., one having the reversed series field, and the other the variable 
resistance controlled by the governor—the combination switch, 
circuit-breaker, and other connections of the diagrams being essen¬ 
tially the same. 

Six=Volt; Two=Unit; Single=Wire 

Generator. This generator is a bipolar machine of the shunt- 
wound type, a section of which is illustrated in Fig. 251. As installed 
on the Westcott (1917)—a wiring diagram of this installation being 
illustrated in Fig. 255—the generator is driven from the water-pump 
shaft through a one-way clutch, that is, a type that will drive when 
turned in one direction but will run free when driven in the opposite 
direction. This permits the generator armature to revolve when the 
engine is not running, thus preventing a heavy current discharging 
through the generator from the battery when the ignition switch is 
turned on while the engine is idle. This is due to the fact that the 


384 


ELECTRICAL EQUIPMENT 


same switch which closes the ignition circuit puts the generator in 
circuit, as explained in connection with the wiring diagram. If the 
generator armature could not revolve, its resistance would be very 
low, so that a heavy discharge would take place, but as it is permitted 



Fig. 251. Generator of Delco Two-Unit System 
Courtesy of Dayton Engineering Laboratories Company, Dayton, Ohio 

to become motorized, its armature builds up a strong counter e.m.f., as 
explained under Electric-Motor Principles, Part I,, thus greatly 
increasing the resistance and greatly decreasing the amount of current 
that will pass through it. 



Regulation. The regulation is of the third-brush type, which 
has already been explained in detail in connection with the single¬ 
unit Delco system. 

Starting Motor. Fig. 252 shows a longitudinal view of the start¬ 
ing motor fitted with the Bendix drive, while an end view of the motor. 




































































































































































































ELECTRICAL EQUIPMENT 


385 


Motor Commutator 



Fig. 


illustrating the commutator and brushes, is shown in Fig. 253. This 
motor is of the multipolar type, and its method of control differs from 
the single-unit type in 
not employing the brush 
switch. 

Starting Switch. A 

pedal-operated plunger 
type of switch is employed, 
for which the advantage 
is claimed that its con¬ 
tacts are self-cleaning. 

The method of effecting 
this will be apparent from 
the part-sectional view of 
the switch. Fig. 254. The 
switch is in barrel form, 
with the springs incor¬ 
porated in the plunger, 
while the stationary and 
movable contacts are given 
a contour that causes them 
to scrape against each 
other when coming into 
contact, thus keeping 
these surfaces bright. 

Wiring Diagram. By 
comparing this wiring dia¬ 
gram, Fig. 255 with Fig. 

2 5 0, which shows the 
single-unit Delco system 
as installed on a Buick 
machine, a clearer idea 
of the difference in the 
requirements of the single- 
and two-unit sets, where 
their circuits are con- 


253 . End View of Delco Starting Motor, 
Showing Commutator and Brushes 


-Foot Dutton 



Terminal • 

'Jtudo- 

Fig. 254. Part Section of Delco Starting Switch 


cerned, will be obtained. It will be noted that the connections of 
the lamps, ignition, and horn are the same, though the method for 






























































































ececT^ic CLOCK 


386 


ELECTRICAL EQUIPMENT 


5 ^» 
Sf o 


0 

eE^ 

8 ! ^ 






o 






CMHon av^H 


> o 
O '' 


K 

>1 

£ - 
K ^ 


OHii"- C^ii"- 



^l|l|Hi"‘ 


•) 5 


Fig. 255. Complete Wiring Diagram of Delco System on 1917 Westcott Cars 






















































ELECTRICAL EQUIPMENT 


387 


controlling them differs. Likewise that all of these, with the 
exception of the ignition, are protected by the circuit-breaker. The 
lighting circuits appear more complicated simply because there is 
an extra light (tonneau light) and two additional accessories, i.e., a 
connection for an electric cigar lighter and one for an electric clock. 

The chief difference is in the generator and the starting-motor 
circuits. An unusual feature in this essential is a two-part switch 
member which controls the ignition and the generator circuits. By 
this method, opening the ignition switch opens the circuit between 
the storage battery and the generator, so that a battery cut-out is 
dispensed with. There is, even under the most favorable conditions, 
a perceptible interval between the closing of the ignition switch and 




Fig. 256. Front and Reverse Face of Combination'Switch for Delco Two-Unit System 

the starting of the engine, and in winter this may be increased to a 
considerable period, during which there will be a heavy discharge from 
the battery through the generator, unless means to avoid it be pro¬ 
vided. The way this is accomplished is by the employment of a one- 
w^ay driving clutch on the generator, as already described. When 
running, the generator is driven by the pump shaft of the engine in 
one direction; when the battery current passes through it, it is free to 
run as a motor in the opposite direction, despite the fact that the 
engine is idle. While operating as a motor, its resistance is sufficiently 
high to cut this discharge from the battery to negligible proportions. 
As soon as the engine starts, the generator is driven in the opposite 
direction, and its voltage immediately overcomes that of the battery, 
and the battery begins to charge. 

























388 


ELECTRICAL EQUIPMENT 


The face of the starting switch and the details of the connections 
on its reverse are shown in Fig. 256. 

Delco Instructions 

General Instructions. If the starter, lights, and horn all fail, 
the trouble is in the storage battery or in its connections, one of the 
connections being loose or corroded, or one of the battery jars being 
broken. When the lights, ignition, and horn all work normally but the 
starter fails to operate, the trouble is in the motor-generator, or dyna- 
motor, and may be caused by the motor brush switch not dropping on 
the commutator, or by dirt or grease on the commutator. Owing to the 
heavy current required by the motor in starting, if the lights are on 
at the time, they will become dim when the starting circuit is closed 
but remain so only momentarily. In case they go out or become 
very dim when the starting-motor circuit is closed, it indicates that 
the battery is practically depleted. When the motor fires properly 
on the M button of the combination switch, but not on the B button, 
the wiring between the dry cells or the connection from the dry 
cells to the combination switch must be at fault. When the igni¬ 
tion works all right on button B, but not on M, the trouble must 
be in the leads running from the storage battery to the generator, 
or in the lead running from the small terminal on the generator to 
the combination switch, or in the battery connections, either of the 
cells themselves or the ground connections. If the supply of cur¬ 
rent from both the dry cells and the storage battery is ample, yet 
both ignition systems fail, trouble should be sought first at the timer 
contacts, then the coil, resistance unit, and the condenser. An 
examination of the timer contacts will show whether they are clean, 
square, and in good working condition; if badly burned and pitted, 
true them up square with a strip of fine emery cloth or a very fine 
fiat file. The coil, resistance unit, and condenser may be tried out 
with the test-lamp outfit. If the lamp lights when contact is made 
through the terminals of the coil or the resistance unit, it indicates 
that nothing is wrong with them, but if it lights on the condenser it 
shows that the insulation of the latter has broken down, as there 
should be no circuit through the condenser. The only remedy is 
to replace it. All of the units mentioned work in the same capacity 
for each system of ignition. 


ELECTRICAL EQUIPMENT 


389 


If, for purposes of making tests, it becomes necessary to remove 
any of the electrical apparatus from the car, or to make any adjust¬ 
ments, the storage battery should first be disconnected. This can 
be done most conveniently by removing the ground connection and 
winding the bare terminal with electrician’s tape so that it cannot 
come in contact with anything that would cause a short-circuit. 
The car should not be run with the storage battery disconnected 



Fig. 257. Diagram Showing Method of Adjusting Third Brush in 1916 Delco Generator 

from the generator or with the battery off the car unless the gener¬ 
ator is short-circuited, as otherwise serious damage may result, as 
the generator is likely to be burned out. 

Adjusting Third Brush. One of the advantages of the third- 
brush method of regulation is the ease with which the output of the 
generator may be varied. It has been found that on some of the 
1916 models of the Delco system the generating capacity (as adjusted 
at the factory) has been set too high, especially for cars which are 















































300 


ELECTRICAL EQUIPMENT 


driven a great deal during the day and very little at night. As a 
result, considerable more current is generated than can be used to 
advantage. An indication of this will be found in the frequent 
necessity for adding water to the cells of the battery, or the fact that 
the battery is constantly gassing. In a case that recently came to 
the writer’s attention, the owner of the car complained that the bat¬ 
tery was no good because it was always hoiling. It boiled so con¬ 
tinually and so violently that it eventually had to be replaced. The 
complaint, in the average case, is that the battery is undercharged 
rather than overcharged. Unless trouble is experienced because of 
the battery gassing too much or needing water too frequently, the 
charging rate should not be altered. When necessary, the alteration 
may be made as follows: It will be noted in Fig. 257 that the third 
brush is carried on a brush arm made in two pieces and that the part 
to which the brush is fastened has a slot through which pass two 
screws, attaehing it to the other part. By loosening these screws, one 
part may be slid on the other, thus increasing or decreasing the length 
of the arm. When the arm is shortened, the charging rate is decreased; 
and when the arm is lengthened the charging rate is increased. Care 
should be taken to sand-in the brush whenever it has been shifted in 
order to insure good contact with the commutator. (See Instructions 
for Seating Generator and Motor Brushes.) The screws on the brush 
arm must be firmly tightened after adjusting to prevent slipping. 

The charging rate of this type of Delco generator is higher at low- 
car speeds than on some machines of an earlier type, so that the 
maximum should be kept somewhat below the value that would 
be used for earlier machines. In most cases 14 to 16 amperes will be 
ample, and in no case should it exceed 20 amperes. Readings should 
be taken at the ammeter on the cowl switch, which indicates the 
amount of current going to the battery but does not include 
the ignition current. 

The foregoing instructions for altering the charging rate apply 
only to machines having the third brush mounted on an adjustable 
arm, as different methods of moving the brush are provided on other 
types. The principle of adjustment, however, is always the same, 
i.e., moving the third brush closer to the nearest main brush increases 
the output and moving it away from this brush, decreases it. The 
third brush must never be allowed to come in contact with the main 


ELECTRICAL EQUIPMENT 


391 


brush. In the case of the Delco generator under consideration, the 
charging rate should reach a maximum at a speed of 15 to 20 miles 
per hour and then drop off as the speed increases beyond this point. 

Tests of Wiring. Locating Grounds. By referring to any of the 
Delco diagrams of the one-wire type, it will be noted that certain 
parts of the circuits are normally grounded, i.e., they are connected to 
the common return represented by the chassis of the car. For 
example, the negative battery terminal, one terminal of each lamp, 
one motor, one generator brush, one timer contact, one terminal 
of the horn push button, and one terminal of the condenser in the coil 
are grounded. Before testing the wiring for grounds, it will accord¬ 
ingly be necessary to remove these normal, or intentional, grounds. 
This is carried out, in the order in which thev are mentioned, bv 
disconnecting the negative battery lead and removing all the lamps, 
placing a piece of cardboard between each generator and each motor 
brush, including the third brush of the former and the commutator 
against which it ordinarily bears, disconnecting the leads from 
the horn button and from the distributor, and raising the base of the 
ignition coil so that it is insulated from the top cover of the generator 
motor. The system will then be in the condition shown in Fig. 258. 

One of the test points is then placed on the frame of the car and 
the other point on the negative terminal A of the battery. If the 
lamp lights, it will indicate a ground somewhere on the switch or in 
the motor windings (all of the switch buttons being pushed in). 
Then, with one test point still grounded on the frame of the car, test 
with the other point the different terminals of the combination 
switch. If the lamp lights during this test, it will indicate a ground 
on that particular circuit, which can be remedied without any par¬ 
ticular difficulty. 

Locating Shorts. To test for short-circuits between wires that 
are normally insulated from each other, place one test point on the end 
of one wire and the second test point on the end of the other, as shown 
in Fig. 259. If the lamp lights, it will indicate a short-circuit between 
these two wires, which can then be carefully inspected to locate the 
exact position of the fault. Failure of the lamp to light when the test 
is made will indicate that the wires in question are in good condition; 
the tests can then be applied to other parts of the circuits which 
should be insulated from each other. 


CoMBtf^ATfON 3wirCM_^ 


392 


ELECTRICAL EQUIPMENT 



Fig. 258. Wiring Diagram Showing Method of Using Lamp-Testing Set for Locating Grounds 
Courtesy of Dayton Engineering Laboratories Company, Dayton, Ohio 


























































ELECTRICAL EQUIPMENT 393 






















































394 


ELECTRICAL EQUIPMENT 


Locating Breaks in Wires. Where the failure of the apparatus 
in a particular circuit makes it apparent that a wire, or lead, may be 
broken, it may be tested by placing one of the points on each end of 
the wire in question. The lighting of the lamp will indicate that there 
is a complete circuit through the wire, while its failure to light is 
evidence of a break in the wire. If at all difhcult to locate the break, 
the easiest method of repairing it is to replace the wire with a new lead 
of the same size and type of insulation. The method of carrying 
out this last test is illustrated in Fig. 260 and it is naturally applicable 
to any of the wires, not only of this type of installation but of any 
other lighting and starting system. In making this test, care must be 
taken not to apply the points at places on the terminals where a 
ground connection will result, as this will complete the circuit through 
the lamp without the current passing through the wire supposedly 
under test. This method of locating grounds, short-circuits, or 
open circuits will be found much better than the use of a buzzer, bell, 
or magneto, and it is recommended wherever a 110-volt current is 
available. However, where it is not available, a lamp, bell, buzzer, 
or the portable voltmeter may be used in connection with the storage 
battery on the car, after detaching its usual connections to the 
system. 

Testing Cut=Out. If the battery is not charging properly, the 
generator being in good condition, or it is discharging too much 
current through the cut-out, the latter should be tested and adjusted 
to remedy the trouble. The cut-out is designed to close when the 
voltage across the terminals of the voltage coil is 6| to 7f volts. 
To check this a voltmeter should be connected across the terminals, 
noting the reading at the point that the contacts close. It is 
designed to break the circuit when the discharge current is less than 
1 ampere, preferably as close to the zero mark as possible to reduce 
the arc on breaking the contacts. This can be checked by placing 
an ammeter in the circuit in series with the current coil of the cut¬ 
out, noting the value of the current at the moment that the contacts 
separate. When properly adjusted the air gap should be inch. 

To adjust the cut-out, the influence of both the air gap and of 
the spring tension must be taken into consideration. The air gap 
has little or no effect upon the point of cut-out, this being governed 
almost entirely by the spring tension, whereas the point of cutting 


^OMdlNAr/OAf ^3wfTCN 


ELECTRICAL EQUIPMENT 395 



Fig. 200. Wiring Diagram Showing Method of Using Lamp-Testing Set for Discovering Breaks in Wires 
Courtesy of Dayton Engineering Laboratories Company, Dayton, Ohio 




























































396 


ELECTRICAL EQUIPMENT 


ill is governed by both the air gap and the spring tension. The 
following examples will illustrate the adjustments necessary in cases 
of excess voltage and current, excess voltage alone, insufficient volt¬ 
age and excess current, and insufficient voltage alone. 

Where the relay cuts in at 8 volts and cuts out when the discharge 
current is 2 am'peres: Decrease the air gap, as this will lower the 
voltage of the cut-in point, but it will also increase the discharge 
current on cutting out. To overcome the latter, increase the spring 
tension slightly, noting the effect on the ammeter until the latter 
registers less than 1 ampere on cutting out. 

Where the relay cuts in at 8 volts and cuts out at 1 ampere: 
Decrease the spring tension as this will cause the relay to cut in at a 
lower voltage and also to cut out after the current starts to dis¬ 
charge through it. 

Where the relay cuts in at 6 volts and cuts out at 2 amperes: 
Increase the spring tension, causing the relay to cut in at a higher 
voltage and also to cut out at a discharge-current value of less than 
2 amperes. 

Where the relay cuts in at 6 volts and cuts out with a discharge 
current of 1 ampere: Increase the air gap slightly and also increase 
the spring tension so as to cause the relay to cut in at a higher volt¬ 
age and also cut out at a discharge current of less than 1 ampere. 

In this connection cut in signifies the closing of the contacts 
when the voltage coil becomes energized as the generator starts up; 
cut out indicates the opening of the generator battery circuit when 
the current from the battery reverses the polarity of the current 
coil of the relay, thus opening the circuit and cutting out the gener¬ 
ator from the battery circuit when the generator slows down and 
there is insufficient voltage for charging the battery. While these 
instructions apply particularly to the Delco relay or cut-out, all 
devices of this nature operate on the same principles. 

Before making any adjustments, the contact points should be 
examined. If they are blackened or pitted, take two narrow strips 
of emery cloth about f inch wide and both the same length. Place 
them together, emery sides out, insert between the contacts and 
while an assistant holds the points together, draw back and forth. 
If no assistance be obtainable, use a single strip and apply alter¬ 
nately to each contact point until its face is bright all over and true 


ELECTRICAL EQUIPMENT 


397 


so that when the two points come together they touch evenly all 
over their surfaces. Do not take off any more than is necessary for 
this purpose, particularly where the contacts are platinum, as this 
simply wears them away uselessly and they are very expensive to 
replace. After cleaning, test for cutting in voltage and cutting out 
current and it frequently will be found that no adjustment is 
necessary. 

These instructions regarding the cleaning of contact points 
apply with equal force to all instruments having contacts by means 
of which the circuit is frequently made and broken, for even platinum 
is burned away by the electrical action of the current which tends 
to carry the metal of the positive contact over to the negative in 
finely divided form, thus making a hole, or crater, on the positive 
and a cone, or peak, on the negative. 

If the contacts are too badly burned to permit of their being 
put in good condition in this way, it will be necessary to replace 
them. After the relay has been reassembled with the new contacts, 
it should be adjusted in accordance with the instructions already 
given’. When the contacts are correctly adjusted, both pairs will 
make contact at the same instant and clear across the line of con¬ 
tact so that when the relay is held up to the light, it is impossible to 
see light passing through any portion of the line of contact. When 
adjusting the relay make sure that all insulating bushings are in 
good condition and that the connections and coil terminals are free 
from breaks or grounds, as these would cause uncertainty in its 
operation. 

Testing Circuit=Breaker. In case the circuit-breaker vibrates 
constantly, it indicates a ground in one of the circuits. Should it 
continue to vibrate when all of the buttons of the combination 
switch have been pushed in, the ground will almost invariably 
be found in the horn or its connections. In case no ground can be 
found in any of the circuits with the aid of the testing lamp, and the 
circuit-breaker still continues to vibrate, connect the portable test¬ 
ing ammeter in the circuit, using the 30-ampere shunt. Then hold 
the circuit-breaker closed and note the ammeter reading when it 
opens. This must be done quickly as the current necessary to keep 
it operating is small so that the ammeter reading will quickly drop 
to a value of 3 to 5 amperes. However, the circuit-breaker should 


398 


ELECTRICAL EQUIPMENT 


not open on a current of less than 25 amperes. If the ammeter 
reading indicates that it does so, increase the tension of the spring 
until the current necessary to operate it shows that it is properly 
adjusted. In case the instrument shows that the circuit-breaker is 
opening at the proper point but still continues to vibrate, another 
series of tests for a ground must be made as the latter is the cause 
of the trouble. 

Seating the Brushes. To insure proper operation of the machine 
either as a generator or as a motor, it is necessary that the brushes 
fit the commutator exactly and that they make good contact over 
their entire surface. If they do not, sparking will occur and the com¬ 
mutator will become burned and blackened, cutting down the 
efficiency of the machine. The brushes are the only wearing parts 
of a direct-current generator or motor, and, as this wear on them 
is constant, they will require'attention at intervals to keep them in 
good condition. Whenever sufficient wear has taken place to make 
the contact uneven, the brushes must be fitted to the commutator 
or sanded-m. Cut a sheet of No. 00 sandpaper in strips slightly 
wider than the brush. Emery cloth must never be used for this 
purpose. It is metallic and will tend to cause short-circuits in the 
commutator. The strip of sandpaper is wrapped around the com¬ 
mutator so as to make contact with at least half of its circumference 
in the manner illustrated in (a) and (c) of Fig. 261. The smooth side 
of the paper is laid on the commutator so that the sanded side rubs 
the brush. By drawing the sandpaper back and forth, it is possible 
to fit the brush very accurately to the commutator. It will be 
obvious that if the sandpaper be applied to the commutator, as 
shown in (b) and (d) of the same illustration, that the brush will 
only touch at its center and there will be excessive sparking between 
the gaps thus formed. 

A high squeaking note caused by the operation of either the 
generator or motor is an indication that either the brushes or 
the commutator need sanding-in as the latter will become roughened 
from the wear. It should be smoothed up by taking strips of the 
same grade of sandpaper sufficiently wide to cover the commu¬ 
tator, applying them by wrapping in the same manner but with the 
sanded surface on the commutator bars. This can be done most 
effectively by running the machine through its other commutator 



ELECTRICAL EQUIPMENT 


399 


for a few moments while holding the sandpaper strip in place on 
the first. If, after this smoothing up, the mica insulation between the 
bars of the commutator is flush with the surface of the copper bars, 
it must be undercut as directed in the following section. On most 
of the Delco machines it will be found possible to sand-in the upper 




and lower brushes separately by this method, but in a number of 
cases on account of the construction of the machine, it will be found 
advisable to sand-in both motor brushes, as well as both generator 
brushes at the same time. It is unnecessary to lubricate either the 
motor, the generator brushes, or the commutators, as this simply 
results in gumming them and causes grit and dirt to collect on 
the commutator and cut grooves in both it and the brushes. 


























































400 


ELECTRICAL EQUIPMENT 


Commutator Maintenance. In the course of time, the com¬ 
mutator bars of the generator will wear down until they are flush 
with the mica insulation separating them. When this occurs there 
will be excessive arcing at the brushes which, in turn, will cause the 
copper to be burned away until it is level with, or below, the surface 
of the mica. This condition will be indicated by a rusty black color 
on the commutator bars. To prevent this condition progressing 
too far, the commutator should be inspected at intervals and cleaned 
occasionally with sandpaper as directed. Should this cleaning show 
that the mica is high, it should be undercut as follows: 

The armature is removed from the machine and placed in a lathe, truing up 
both commutators until they are perfectly concentric. This should be done 
carefully and then as fine a cut as possible taken to avoid wasting the copper 



storting groo\/G m mtco 
with 3-cornered file 




CcJ 


/^loa rrtust be cut 
clean between segments. 


tiica muai not be left wcth 
a thin ed^ next to se^manta 


Fig. 262. Method of Undercutting Mica Insulation on Commutator 


needlessly. When the commutators have been trued up in the lathe, cut out mica 
between the commutator bars of the generator only. For this purpose a piece of 
hacksaw blade should be fixed in a handle, as shown in Fig. 262, and its teeth 
ground off until they will cut a slot that is just slightly wider than the mica insu¬ 
lation. The cut need not be more than inch deep. In this way a rectangular 
slot, free from mica, will be obtained between each two adjacent commutator 
bars. After undercutting the mica, the edges of these slots should be beveled 
very shghtly with a three-cornered file in order to remove any burrs which would 
cause excessive wear of the brushes. 

It is unnecessary to undercut the mica on the motor commutator, as, wherever 
metal or metallic brushes are used on Delco machines, they are sufficiently hard 
to keep the mica flush with the surface of the copper as it wears down without 
any undue arcing at the brushes, whereas in the case of generators provided with 






















































ELECTRICAL EQUIPMENT 


401 


carbon brushes, the carbon is not hard enough to do this. After completing the 
undercutting, the commutator when viewed from the end should show clean-cut 
rectangular slots between the bars, as in the left-hand view. Fig. 262. The 
machine should then be reassembled and the brushes sanded-in to the commu¬ 
tator, as previously described. This operation of fitting the brushes to the com¬ 
mutator wall be necessary w'henever anything has been done to the commutator, 
when new brushes are installed, or when the third-brush location is readjusted 
to vary the output of the machine on generators having this type of regulation. 

These instructions for fitting the brushes, cleaning the com¬ 
mutator, and undercutting the mica of the commutator of any 
machine equipped with soft-carbon brushes, apply with equal force 
to all makes of generators and starting motors employed on auto¬ 
mobiles. Next to the battery the brushes and commutators will be 
found to demand most attention—or to put it another way, they will 
be found to constitute a cause of trouble only second in importance 
to the battery. It must not be assumed, however, that all black¬ 
ening of the commutator is caused always by high mica. Any one 
of the following conditions may cause the commutator to assume 
an appearance similar to that produced by high mica: (1) generator 
brushes of improper size or material, as where replacements other 
than those supplied by the manufacturer of the machine have been 
installed; (2) insufficient spring tension on brushes—all springs 
slacken up in time and they should be examined at intervals to see 
that the brushes are being held firmly against the commutator; (3) 
overloading of the generator caused by partial failure of the regu¬ 
lating device or other cause; and (4) an open- or short-circuit in the 
generator windings, or a short-circuit between generator and motor 
windings in a single-unit machine like the Delco. 

Testing Armatures. In reading the foregoing instructions as 
well as those that follow here concerning the Delco system, it should 
be borne in mind that they apply in principle, and in many cases in 
actual detail, to the majority of other systems described. In other 
words, all starting and lighting systems are based on the same prin¬ 
ciples and, while many of them differ in detail and in design, the 
application of the instructions in question will very frequently be 
evident by comparing them point for point and modifying the instruc¬ 
tions to compensate for any slight differences in design or wiring. 

Armature troubles are of much less frequent occurrence than the 
majority of defections, such as worn brushes, dirty commutator, or 


402 


ELECTRICAL EQUIPMENT 


the like, which temporarily put the system out of commission, so that 
every part of the system which might be at fault should be investi¬ 
gated before attempting to test the armature for faults. To carry 
out these tests, the voltmeter and the lamp-testing set are necessary. 
Where no previous experience has been had in making tests with these 
aids, it will be well to become familiar with the detailed instructions 
given for their use in connection with the determination of other 
faults, as already described. It is not necessary to remove the dyna- 
motor from the car for this purpose. When tests of the remainder 
of the system indicate no faults and when grounds in the armature 

windings or short-circuits 


C^Mo /or Co/nrnuktfor 


/lrma!ure 
^haft 


Gerrerarjr 

Commutafof' 



m Lamp\ 



between them are not 
suspected, raise all the 
brushes from the commu¬ 
tator and slip pieces of 
cardboard between the 
brushes and the commu¬ 
tator so as to insulate 
them from each other. 
These instructions cover 
the single-unit Delco 
machine, so the foregoing 
applies as well to testing 
for short-circuits between 
generator and motor 
armature windings. For 
greater simplicity, the 
possible faults and the tests for locating them are treated under 
different heads, as follows: 

(a) Growided Generator Coil. On one-wire systems of the 
single-unit type, the presence of a grounded generator coil will mate¬ 
rially reduce the charging rate to the battery and will also result in 
slow cranking of the engine. To determine whether a generator 
coil has become grounded, place one of the test points on the frame or 


//ovoitac.or/j.c. 
Fig. 263 


Diagram for Locating Grounded Generator Coil 
with Lamp-Testing Set 


on the armature shaft, both of which are grounded, and the other on 
the generator commutator, as shown in Fig. 263. If the lamp lights, 
it indicates a ground on the commutator. The test of the generator 
of a two-unit set would be carried out in exactly the same manner. 










































ELECTRICAL EQUIPMENT 


403 


/Jrmafure 


ffenerafor 

Commutatof 


(b) Grounded Motor Coil. According to the nature of the fault, 
a grounded motor coil may either prevent operation of the starting 
motor altogether or it 

1, 1 • f - . —-■■ ■ ■—■ (>Mo/or Commutafor 

may result only m an ^_ 

excessive consumption of 
current for starting. The 
test is carried out in the 
same manner as described 
for the generator, except 
that the second point of 
the test set is placed on 
the motor commutator. 

Fig. 264. It will likewise 
be evident that an inde¬ 
pendent starting motor 
can be tested in the same 


way 



//Oyo/rLamp(^^ 


(c) Short-Circuits 
between Motor and Gener¬ 
ator Armature Coils. In 
most cases short-circuits 
between motor and gener- 
rator armature coils will 
decrease the speed of 
cranking and will cause 
the armature to continue 
to run after the engine 
has been shut down. 
This test is carried out 
by simply placing one 
test point on the gener¬ 
ator commutator and the 
other on the motor com¬ 
mutator. If the lamp 
lights, it indicates a short- 
circuit between the gener¬ 
ator and motor windings, 
Fig. 265. This test is 


//^ Vo ft D.C. or/i.C. 

Fig. 264. Diagram for Locating Grounded Motor Coil 
with Lamp-Testing Set 


Motor Vmmafafor 
Generator 
Commutator 



//O Vo/fLamp 



J/tJ Vo/f D.C.or/l.C. 

Fig. 265. Diagram for Locating Short-Circuits between 
Motor and Generator Armature Coils 






























































































404 


ELECTRICAL EQUIPMENT 


r 


naturally only applicable to single-unit machines having two inde¬ 
pendent windings on the same armature core, as in the case of the 
Delco, the type in question. 

(d) Open- or Short-Circuited Generator Armature Coils. When 
testing for open- or short-circuited generator armature coils, the gener¬ 
ator brushes should be left in contact with the commutator, but the 
storage battery should be disconnected from the system, carefully 
taping the loose battery terminals before proceeding. Then discon¬ 
nect the shunt field from the brushes and tape these terminals so that 
they do not accidentally come in contact with the frame or other parts 



Fig. 26G, Diagram for Testing Open- or Short-Circuited Generator 
Armature Coil with Ammeter 


of the unit. Connect up a dry cell and the portable ammeter, using 
the 30-ampere shunt, as shown in Fig. 266. Turn the armature over 
slowly by hand. If the commutator is clean and bright and the 
brushes are making good contact with it, a very noticeable change in 
the ammeter reading will indicate an open- or a short-circuited 
armature coil. To determine whether the coil is open- or short- 
circuited, the following tests should be made: 

(1) Open-Circuited Coils. Connect the brushes to the 
terminals of the dry cell so that a current of about 10 amperes is 
flowing through the brushes. The field should be entirely dis¬ 
connected and its terminals either taped or held out of the way. 
Then, with a special pair of points connected to the voltmeter. 






























ELECTRICAL EQUIPMENT 


405 




Dr^ Cell—* 




Fig. 267. Diagram of Set-Up when Coils Are Open-Circuited 



Cell 



Fig. 268. Diagram of Set-Up when Coils Are Short-Circuited 





















































406 


ELECTRICAL EQUIPMENT 


using the 3-volt scale, measure the voltage across each two 
adjacent commutator bars. If there is an open-circuited coil in 
the armature, the voltage reading will increase considerably. 
Fig. 267. 

(2) Short-Circmted Coils. If there are no open-circuited 
coils and the preceding tests indicate that there is trouble with 
the armature, it should be tested for short-circuited coils. This 
should be done only after the preceding tests have been made, as 
an open-circuited coil might cause the .1-volt scale of the volt¬ 
meter to burn out if this test were made first. The armature is 
connected as indicated in(l) above, but for this test the.l -volt 
scale instead of the 3-volt scale of the voltmeter is used. Fig- 268. 
The voltage drop between adjacent commutator bars is then 
measured by slowly turning the commutator over by hand. 
The readings should be approximately the same. If any of them 
drop nearly to zero, it will indicate that one or more of the arma¬ 
ture coils are short-circuited. In taking these readings, care 
must be observed to keep the points always on adjacent commu¬ 
tator bars and not allow them both to come on the same bar at 
any time; otherwise, the voltage drop may be sufficient to injure 
the voltmeter. 

Should any of these tests indicate open- or short-circuited 
coils in the armature, it is advisable to send the armature to 
the manufacturer for repairs, or to install a new armature. 
Unless the fault is plainly visible, as where a coil-terminal con¬ 
nection at the commutator bar has broken or become short- 
circuited, the average establishment will find the repair entirely 
beyond its facilities to make, so that time and expense will be 
saved by promptly referring it to the factory. Special equip¬ 
ment and skill in the handling of such repairs are indispensable 
and are beyond the province of the garage man. 

Testing Field Coils. The tests of field coils are simpler than 
those of the armature, and they apply in large measure to practically 
any system. 

Open-Circuits in Fields. To test for open-circuits in fields, the 
test set is the only apparatus required, and the points should be 
placed as shown in Fig. 269. By placing one point on each terminal 
of the particular winding to be tested, failure of the lamp to light 


ELECTRICAL EQUIPMENT 


407 


H 



F'ield Coil 



i/0 Volt Lorr^ 


HO Volt 


n.C. Or D.C. 


Fig. 2G9. 


Diagram for Locating Open Circuits in Field 
Coils with Lamp-Testing Set 


will indicate that the coil is open-circuited, as the wire of the coil will 
afford a path for the current, unless broken. The fact that the lamp 
may not light to full bril¬ 
liance in some of these coil 
tests is no indication of 
trouble, as the difference 
is simply due to the addi¬ 
tional resistance repre¬ 
sented by the coil itself. 

In case an open-circuited 
coil is found, the only 
remedy is to return it to 
the manufacturer for 
repair or replacement. 

Grounded Fields. To 
test for grounds in the field windings, place one test point on the 
frame of the machine and the other on a terminal of the field coil. 
Before doing this, however, all intentional ground connections made 
by the terminals should be removed. These can be located by 
referring to the winding diagram. If the lamp lights, it will indicate 
a ground. The manner of 
applying the test points is 
shown in Fig. 270. 

Short-Circuits between 
Windings. To test for 
short-circuits between 
windings not normally con¬ 
nected, as for example the 
shunt and series winding 
of.a field coil, place one 
test point on the terminal 
of one winding and the 
other test point on the terminal of the other field winding, as shown 
in Fig. 271. If the lamp lights, it will indicate a short-circuit 
between the windings. The field coils can also be tested with a 
voltmeter, the 30-volt scale being used in connection with a 6-volt 
storage battery for this purpose. Fig. 272. Detailed instructions 
for the use of the instrument are given in a previous section. As 



F'ield Coil 

Motor-Qenerator Mrarne 


ri 

U 


©' 


HO Volt Lamp 


no Vol I 


n.C. Or D.C. 


Fig. 270. Diagram for Locating Grounded Fields 
























408 


ELECTRICAL EQUIPMENT 



shunt F'ield Coil 


Series Field Coil 


^AAA/Wf 


no Vol t L amp 


IW Volt 


fi.C. OrD.C 



Fig. 271. 


Diagram for Testing Short-Circuits 
between Windings 


all lighting generators have more than one winding on their fields, 
i.e., shunt and series windings (the latter termed ‘Tucking coils” when 
reversed), these tests are equally applicable to all makes. 

Voltmeter Field Tests. 
The method of employing 
the voltmeter for making 
field tests, shown in Figs. 
272 and 273, is as follows: 

To test for an open- 
circuited field, connect up 
as shown in Fig. 272. The 
positive terminal of the 
voltmeter is connected to 
the positive terminal of 
the battery. An insulated 
copper wire of convenient 
length, with the insulation 
stripped off for about one inch at each end, is then attached to the 
terminal of the voltmeter marked “30 volts”, and a similar wire is 

attached to the negative 
terminal of the battery. 
The free ends of these 
wires are then used in the 
same manner as the points 
of the test set, except that 
the voltmeter reading is 
the indication sought 
instead of the lighting of 
a lamp. Before making 
the test, touch the free 
ends of the wires together. 
This reading will be the 
total voltage of the stor¬ 
age battery, and it should 
be kept in mind when 
making the tests. 

If, instead of touching the free ends of the wire together, they are 
placed on the terminals of a high resistance, the voltmeter reading will 





























ELECTRICAL EQUIPMENT 


409 


naturally be much less. In other words, the value of the voltmeter 
reading will always depend upon the amount of resistance offered 
by the coil or other circuit that is being tested. When there is no 
circuit, as with the free ends held apart in the hands, there will be 
no indication on the voltmeter scale. An open-circuited coil will 
accordingly be indicated by a zero reading of the voltmeter when the 
two free ends, or points, are placed upon the terminals of the coil, 
Fig. 272. If, on the other hand, the voltmeter reading is nearly half 
of that of the battery voltage, the coil is in good condition. This test 
corresponds to that with the lamp-testing set using the 110-volt 



Fig. 273. Voltmeter Test Diagram for Short-Circuit between Coils 

current, illustrated in Fig. 269. It is a method which also permits 
one coil to be checked against another of the same kind, as the read¬ 
ings given by the two coils should be approximately the same. Where 
neither a 110-volt current nor a portable voltmeter are available, these 
tests may be carried out with the aid of a 6-volt bulb in connection 
with the storage battery, as shown for the voltmeter tests. In this 
case, the lamp will light brightly when the free ends of the wires are 
brought together, but it will dim in proportion to the amount of extra 
resistance added to the circuit, as represented by the coil under test. 
While not so accurate as the tests with the voltmeter, comparative 
























410 


ELECTRICAL EQUIPMENT 


tests are also possible with the low-voltage lamp, a very perceptible 
difference in the lighting of the lamp indicating a greatly increased 
resistance. When using current from a storage battery for testing, 
care must be taken to have the points of the test set, or ends of the 
wire, clean and bright, and to make good, firm contact. If necessary, 
l^laces on the machine at which the test points are to be applied should 
first be scraped or filed clean, otherwise, additional resistance will 
be inserted by the poor contact at the points, as for example, where the 
latter are applied to a painted surface. 

To test for grounds in a field, after having removed all ground 
connections, as mentioned in a previous paragraph, place one end, 
or point, on a terminal of the field coil and the other on the frame of 
the machine. The method of making the test is identical with that 
shown in Fig. 270, except for the substitution of the voltmeter for the 
110-volt light circuit. If the coil is free from grounds, the voltmeter 
needle will remain at zero; in case, there is a ground, there will be an 
indication on the instrument and the worse the ground the greater the 
value of this reading will be. This test corresponds to that illustrated 
in Fig. 264. 

Short-Circuits between Coils. The test for short-circuits between 
coils is similar to that shown in Fig. 265 and naturally applies to all 
lighting generators where the two windings of the fields are concerned. 
Place one end, or point, on the terminal of one winding and the 
other end on the terminal of the other winding, as shown in Fig. 273. 
If there is no connection between the coils, as should be the case, 
the voltmeter needle will remain stationary. Any movement of the 
voltmeter needle indicates a short-circuit and the greater the value 
of the reading, the more complete is the short-circuit between the 
two coils. 

In order to make these tests without removing the machine from 
the car, first, disconnect the storage battery and tape the disconnected 
terminals; then, insulate all the brushes by placing pieces of card¬ 
board between them and the commutators. Disconnect all wires 
leading to generator terminals, and, likewise, all wires leading to 
field-coil terminals. By referring to the circuit and wiring diagrams 
for the particular car under consideration, all these leads can readily 
be identified, and after disconnecting them, the field coils of the 
machine can be tested. When the tests indicate that the field coils 


ELECTRICAL EQUIPMENT 


411 


are not in perfect condition, it will usually be found advisable to 
remove the field coils from the machine and send them to the manufac¬ 
turer for repair or replacement, for unless the fault is plainly apparent, 
which will seldom be the case, the repair will usually be found to be 
beyond the average garage facilities. 

DISCO SYSTEM 
Twelve=Volt; Single=Unit 

Dynamotor. The dynamotor is bipolar with both windings 
connected to the same commutator. 

Regulation. Constant current-control regulation by means of a 
vibrating regulator is employed. (See description of the Ward- 
Leonard regulator, Fig. 149, Part IV.) 

Operating Devices. Battery Cut-Out. The cut-out is of the 
conventional type, combined with the current-control regulator. 

Switch. The switch is the spring-controlled type which is only 
closed for starting. 

Six=Volt; Two=Unit 

Units. Both the generator and the starting motor are of the 
bipolar type, the motor being designed to operate through a Bendix 
drive. 

Instructions. As both types of the system are characterized 
by standard features throughout, instructions given in connection 
with other systems apply here. 

DYNETO SYSTEM 

Twelve=Volt; Single=Unit; Single=Wire 

Dynamotor. Non-Stalling Feature. Both windings are con¬ 
nected to the same commutator. No battery cut-out is employed, 
control being by means of a single-pole knife-blade switch, which is 
closed for starting and left closed as long as the engine is running. 
This switch also controls the ignition circuit. Upon closing the 
switch, the dynamotor acts as a starter and turns the engine over; 
as soon as the engine takes up its cycle and drives the dynamotor 
above a certain speed, the latter automatically assunles its functions 
as a generator and begins to charge the battery. Whenever the 
speed drops below that point, the dynamotor again acts as a motor 


412 


ELECTRICAL EQUIPMENT 


to turn the engine over, this characteristic being termed the “non¬ 
stalling” feature of the system. Provided the battery is sufficiently 
charged, the dyriamotor will always act as a starter (the switch 
being closed) whenever the engine is inadvertently stalled or its 
speed drops below the generating point of the machine. 

Instructions. The switch must never be left closed with the 
engine stopped, and when the car is stopped, the engine must not 
be allowed to idle at a very low speed, as in either case the battery 
will be run down. Instructions for lack of generator capacity 
the location of grounds or short-circuits, and the like, are the 

same as for other systems. 

Six=Volt; Two=Unit 

Generator. The gener¬ 
ator is a standard shunt- 
wound machine of the 
four-pole type, haying two 
wound, or salient poles, and 
two consequent poles. (See 
Fig. 219, Part IV.) It is 
ordinarily designed to be 
driven at one and one-half 
times engine speed, but, in 
common with other makes, 
machines wound for higher 

Fig. 274. SectionalJiewSho^^^^^^ 

nished, according to the 

requirements of the engine on which it is mounted. 

Regulation. Regulation is effected by means of a vibrating 
regulator, which is combined with the battery cut-out. This cuts 
in at a speed equivalent to 10 miles per hour, and the generator reaches 
its maximum normal output of 10 to 12 amperes between 12 and 15 
miles per hour. The regulator does not become operative until the 
current flow increases to 10 to 12 amperes, at which point it is held 
regardless of the speed. The details of the combined regulator and 
cut-out are shown in Fig. 274, while all the connections are shown in 
the diagram. Fig. 275. As soon as the dynamo runs fast enough to 
cause it to generate, a portion of the current passes through the 






















































ELECTRICAL EQUIPMENT 


413 


winding A of the cut-out, Fig. 274. This is ordinarily known as 
the voltage winding and is of fine wire, so that very little current is 
required to energize the core and attract the armature B, which closes 
the contact points C and D. These points close the circuit through 
the coil E, which is of heavy wire and is known as the current coil. 
As the current in both coils is in the same direction, their exciting 
effect on the magnet core is cumulative, and the points are held 
together that much more firmly. 

On the upper side of the magnet will be noted another armature 
F and a set of contact points G and II. This armature is subject to the 
same magnetic attraction, but the tension of its controlling spring is 



such that the magnet is not strong enough to move it. This spring 
is so adjusted that any increase in the current beyond this point will 
cause armature F to be attracted, opening points G and H. These 
points are directly in the shunt-field circuit and a resistance coil I is 
connected across them, so that when the points are together, the 
resistance is cut out of the shunt-field circuit; when they separate, . 
this resistance is added to that of the shunt field. With a charging 
rate of 10 to 12 amperes, the tendency toward any higher output with 
increased speed is checked by the almost imperceptible but very rapid 
vibration of the armature F, which cuts the resistance unit in and out 
of the circuit and causes a pulsating current to be sent through the 










































414 


ELECTRICAL EQUIPMENT 



Fig. 276. 


Starting-Motor Circuit for 
Dyneto System 


field windings, thus keeping the output within the required limits. 
When the generator speed falls below the normal rate, the voltage 
drops correspondingly and the battery current overcomes that from 

the generator and reverses the 
current flow through the current 
coil E. This reverses the mag¬ 
netic effect produced, bucking that 
caused by the generator current 
in the coil A, and, as the battery 
current is then superior to the 
latter, the magnetic effect of A is 
neutralized and the armature 
B is forced away, opening the 
contacts C and D. 

Starting Motor. This start¬ 
ing motor is of the standard 
series-wound type of the same 
characteristics of design as the 
generator. In Fig. 276 is shown 
the wiring diagram of the starting circuit and illustrates plainly the 
relation of the series fields B and E to the armature D and 

the brushes E and C. H is the 
starting switch and A and G are 
the cables of a two-wire starting 
system. Compare Fig. 276 with 
Fig. 277, which shows the shunt 
windings of the generator and 
their relation to the armature 
and battery. In Fig. 276 the 
dotted line from G to A illus¬ 
trates a supposed short-circuit 
caused by chafing, or abrasion, of 
the insulation of the wires. 

Wiring Diagrams. Either 
the single- or the two-wire system 
of wiring is employed, according to the car on which the system is 
installed. Fig. 279 shows the one-wire, or grounded, system, and 
Fig. 279 shows the two-wire system. 

















































ELECTRICAL EQUIPMENT 


415 


Instructions. In case of failure to start, the switch should always 
be released instantly and the battery tested to determine its condition 



of charge. If the battery is not run down, examine all connections 
and wiring, for, if a short-circuit exists as indicated by the dotted line 



at G in Fig. 272, no current can reach the motor. Failing to locate 
any short-circuit or ground in the system, open the name-plate cover 
























































































































































416 


ELECTRICAL EQUIPMENT 


on the starting motor and inspect the brushes. Lift each brush 
holder a trifle (if they are in proper condition, they should spring back 
when released) and press the brushes firmly against the commutator. 
(See Gray & Davis instructions for Spring Pressures on Starting 
Motors. These pressures are not the same on all makes, but this will 
give some idea of the high pressure necessary to make the contact 
required to handle the heavy currents used in the starting motor.) 
See that the commutator is clean and the brushes are making uniform 
contact all over their surfaces. Make sure that the two leads from 
the field coils to the brush holders are screwed down tightly. 

When it is necessary to renew the brushes, remove the eight 
screws shown holding the end plate. Remove this commutator 
housing, or end plate, leaving the brush unit in place on the com¬ 
mutator. Remove only one brush at a time and replace it with a new 
one. Note bearing of brushes on commutator and sand-in to a true 
and uniform bearing over the entire surface of the end of each brush. 
When this has been done, carefully clean out all traces of carbon 
dust, using a rag wet with gasoline, if necessary; a small bellows may 
be used to advantage to blow this dust out dry, and will be more likely 
to get it out of the nooks and crannies then wiping. After the brushes 
have been sanded-in and the dust all cleaned out, see that both brush 
leads are tight and then replace the housing. New brushes should 
be necessary only after a year or two of service, sometimes longer; 
old brushes will operate just as efficiently as new ones, provided they 
have a bearing all over their surface and are held firmly against the 
commutator. A brush becomes too short for further use only 
when the spring can no longer hold it in good contact against the 
commutator. When ordering brushes, it must always be specified 
whether they are wanted for the generator or for the motor, and the 
type of machine, as stamped on the name plate, must be given. 
This applies equally to the brushes needed for any make of generator 
or starting motor, and no other brushes than those supplied by the 
maker for the machine in question should ever be used. 

GRAY AND DAVIS SYSTEM 
Six-Volt; Two=Unit; Single-Wire 

Generator. The bipolar generator is designed for drive by 
silent chain, as shown in Fig. 280, or when combined with ignition 
distributor from the pump shaft. Fig. 281. 


ELECTRICAL EQUIPMENT 


417 


Regulation. Earlier types, including the original lighting gen¬ 
erator, were of the constanUspeed type regulated by a governor and 
slipping clutch, which maintained the speed of the generator con¬ 
stant. The 1914 and subsequent models are controlled by a combina¬ 
tion regulator cut-out, usually mounted directly on the generator 
itself. The regulator increases the resistance of the generator-field 
windings in proportion to the increase in speed, thus maintaining a 
steady output. 

Starting Motor. The series-wound bipolar motor is made for 
either open or enclosed flywheel drive, according to the type of car. 
In Fig. 282 is shown the open flywheel type. The illustrations of 



Fig. 280. Section of Gray & Davis Generator for Silent-Chain Drive 


both generator and motor show them with the side plate removed 
for inspection. The type of starting switch employed on later 
models is shown in Fig. 283. The rod passing through the switch 
leads to the pedal on the footboards for operating it. 

Instruments. Either an indicator showing whether the battery 
is charging, discharging, or is neutral, or an ammeter serving the 
same purpose, is supplied. The ammeter is provided with a gradu¬ 
ated scale and its normal readings should be as follows: Standing, 
no lights on, zero; with lights on, discharge 5 to 7^ amperes. Car 
running 6 to 8 miles per hour, lights on, discharge same rate. Above 
8 miles per hour, lights off, charge 5 to 9 amperes; above 10 miles 

















































418 


ELECTRICAL EQUIPMENT 


per hour, lights on, charge 3| to amperes. Under the last-named 
condition, the lights are being supplied directly by the generator 



and only the excess current is charging the battery. Whenever 
the generator output drops below a point where it is supplying 


Fig. 281. Section of Gray & Davis Generator with Ignition Distributor Gearing (Shaft Drive) 
Courtesy of Gray & Davis Company, Boston, Massachusetts 


























































































































































































































ELECTRICAL EQUIPMENT 


419 


sufficient current to light all the lamps that are on, the battery 
supplies the balance. The battery is thus said to be floated on the 



line. It charges or discharges according to the current supply and 
the demand upon the latter. 































































































































































































































































420 


ELECTRICAL EQUIPMENT 


Regulator Cut=Out. The regulator is of the constant-current 
type and on the Chandler, Metz, and Chalmers cars is set to allow the 
generator to produce a minimum of 8.5 amperes and a maximum of 11 
amperes; on the Paige the minimum is the same, but the maximum 
is 12 amperes. 

To Check for Adjustment. Insert the portable ammeter with the 
30-ampere shunt in the circuit between the generator and the regu¬ 
lator and switch on all the lamps. Speed the engine up so that the 
generator is running above 1750 r.p.m. Open the upper set of points 
by inserting a match or using the finger, then adjust the lower set of 
points in accordance with the reading of the, ammeter. Open the 
lower set and adjust the upper in the same way. Run the machine 



Fig. 283. Gray & Davis Starting Switch with Both Terminals Insulated 


with both sets free, and the ammeter reading should fall within the 
limits above given. 

To Check Candle Power of Lamps. These instructions are given 
by the manufacturers in connection with a special bench testing set 
using three 15-c.p. lamps in multiple. Check the candle power of 
the lamps on the car to see that their total does not exceed 45 c.p., as 
25-c.p. headlights are sometimes used. The employment of headlights 
of this high power should be discouraged by the garage man, as they 
needlessly increase the load on the battery and cause a blinding glare. 

To Check for Closing Voltage. The points of the battery cut-out 
are designed to close at 6J to G volts from the generator and are 
















































ELECTRICAL EQUIPMENT 


421 


designed to open on a current of J to 2 amperes from the battery on 
discharge. Connect the low-reading voltmeter, scale 1 to 10 volts, 
across the generator brushes. Gradually speed up the generator and 
note the voltmeter reading to determine the voltage at which the 
points close. If not correct, adjust the cut-out spring to bring 
the closing voltage within the above limits. 

To Check the Cutting-Out Point. Connect ammeter in battery 
and cut-out circuit, using low-reading shunt, 1 to 3 amperes. Have 
the machine running at a speed at which points are closed, and grad¬ 
ually slow down, observing the ammeter reading when the points 


^/r pap at point .0/5' 
Cat out points 

Not te ss ^n n 0 / 0 'pop 



N/rpnp at point 0/0 

///r gap at armature 0/5' 


''//rmafure air gap . 050" 
Cut-out /trmature 

Nit/ustiap srreui 
Loc/< nut 



CC) 

fiirgaps for cut-out. 
f/ex/d/e ar/n tgpe 


f/rmatiire mast depara/e/t mt/ipo/e 


fir gap dacA of point 0/0' 
/tegu/ator points 

fir gap detu/een 
armatures.005 



fir gaps for regu/ator points 


(d) 

fir gaps for cut-out 
So/id arm type 


Fig. 284. Diagram Showing Air Gaps between Parts of Gray & Davis Apparatus 


open. If not within the limits given, adjust the cut-out spring to 
bring them within these limits by tightening or loosening the spring 
tension and repeating the test. Should this not be possible, inspect 
the points to see if they are clean and true, and, if in good condition, 
check the distances of the various air gaps between the points and 
between the armature and the pole piece, or stop, as shown in Fig. 284. 

Wiring Diagrams. The single-wire system is standard, but in 
some cases the motor is grounded and in others the switch. Among 
others, the Gray & Davis system with grounded motor is installed 
on the Peerless, Chandler, Stearns, and Winton; with grounded 
switch, it is installed on the Chalmers, Paige, and Maxwell. It is 






































































































































































































ELECTRICAL EQUIPMENT 


423 


naturally impossible to give complete lists of installations in any 
case, so that only one or two representative makes are mentioned 
to enable certain systems to be identified in the garage when desired. 

Grounded-Motor Arrangement. Fig. 285 shows the Gray & Davis 
wiring diagram with grounded motor. Cable A from the battery 
positive terminal connects to the grounded terminal of the starting 
motor. Cable T connects an insulated terminal on the starting motor 
to one of the starting-switch terminals. Cable C from the starting 
switch terminal connects to the battery negative terminal, thus 
completing the circuit. On some makes of cars, cable A instead of 



Fig. 286. Gray & Davis Lighting Switch, Rear View 


connecting directly to the starting motor is connected to the frame 
of the car or grounded. The car frame carries the current to the 
grounded terminal of the starting motor. Wire D from the end 
of cable C at the starting switch connects to the lower terminal of 
the indicator (or ammeter). Wire P connects dynamo terminal 
L at the regulator to the lower terminal of block B at the lighting 
switch, Fig. 286 showing a rear view of the lighting switch. From the 
terminals at the fused side of 11 at the lighting switch, two wires con¬ 
nect to the right-hand and left-hand head lamps, while from the ter¬ 
minals at the fused side of S on the lighting switch corresponding 
wires connect to the two small lamps in the headlights. The tail lamp 
is connected from the fused side of R on the lighting switch and in 
some cases to the dash lamp, while the electric horn and ignition are 









Fig. 287. Wiring Diagram for Gray & Davis Single-Wire 
System with Grounded Switch 































































































ELECTRICAL EQUIPMENT 


425 


connected to the fused side of B, The various ground connections 
are as follows: battery positive by cable A to frame at grounded 
terminal of starting motor; generator positive terminal to the frame 
of the dynamo itself; one side of all lamps to frame of car. 

Grounded-Switch Arrangement. Fig. 287 is the Gray & Davis 
wiring diagram of the grounded-switch type. The only difference 
between this and the other diagram is that the ground connection 
is taken from the terminal of the cable A to the switch instead of 
from the motor. 

Instructions. When the indicator does not indicate charge 
though the engine is speeded up, but indicates discharge with the 
engine stopped, the dynamo or the regulator may not be working 
properly. To verify this, turn on all the lights, run the engine at 
a speed equivalent to 10 miles per hour, disconnect the wire from ter¬ 
minal B, Fig. 285, at the regulator cut-out; if the lights fail, either 
the dynamo or the regulator is at fault. Reconnect the wire to 
terminal B and remove the side plate from the dynamo to examine 
the brushes. Slide the brushes in and out, and see that thev slide 
freely in the brush holders and make good contact with the commu¬ 
tator and that the wires from the brush holders and the fields to the 
dynamo terminals are firmly connected. If the dynamo is belt-driven, 
the belt may not be tight enough to rotate the dynamo at sufficient 
speed to charge the battery. The commutator, if coated or dirty, 
may be cleaned while rotating by holding a cloth slightly moistened 
with oil against it. 

Should these tests fail to remedy trouble, connect a wire at the 
regulator cut-out from terminal A to terminal B. With lights off, 
speed the engine to the equivalent of 10 miles per hour. If the indi¬ 
cator then shows charge, the regulator cut-out is at fault. Note 
whether any connections on it are loose or broken from vibration. See 
that the contacts are clean and come together properly. Take a match 
stick or small piece of clean wood and press them together; if this 
remedies the trouble, the contact points are at fault. Clean them 
with a strip of fine emery cloth or with a very small fine flat file, not 
taking off any more than is necessary to clean and true up the points. 
In case this treatment does not put the cut-out in working condition 
again, the manufacturer’s service department should be called on 
for assistance. 


426 


ELECTRICAL EQUIPMENT 


But if, under conditions just given, the indicator, or ammeter, 
shows neither charge nor discharge, the dynamo circuity is open. 
This may be from poor brush contact or from a loose or broken 
connection at some other point. If the indicator shows discharge, 
reduce the engine speed to the equivalent of 8 or 9 miles an hour; then 
while the engine is running, connect another wire from the dynamo 
terminals F and Fi to terminal A. If the indicator then shows charge, 
the regulator is at fault, as this wire cuts the regulator out of the 
charging circuit. While making this test, care must be taken not to 
run the engine any faster than mentioned, as the dynamo is not 
protected by the regulator. If in this test, the indicator still shows 
discharge, it signifies that the dynamo field circuit is open or that the 
armature is short-circuited. 

Loose Connections. If with the engine speeded up the indi¬ 
cator does not show charge and with the engine stopped and the 
lights turned on it does not indicate discharge, there is an open or loose 
connection in the battery circuit. See that all the wires are firmly 
connected and that the contact faces are clean. Or the indicator 
itself may be at fault. Verify this by disconnecting one wire from it 
and if it then returns to neutral, it indicates that some part of the 
wiring is grounded on the frame of the car and is causing a short- 
circuit which is discharging the battery. But if after disconnecting 
this wire the indicator shows discharge, it is at fault. See if the pointer- 
is bent. This probably will be the case if it indicates charge with the 
engine stopped. 

Short-Circuits. If the ammeter discharge reading is above 
normal, it may indicate that higher candle-power lamps have been 
substituted for the standard bulbs, or that some of the lamp wires 
are short-circuited. Intermittent jerking of the pointer from charge 
to neutral the engine is being speeded up also indicates a short- 
circuit. Repeated blowing of fuses indicates short-circuited lamp 
wires or defective lamps. Trgce the wires along their entire length 
and try new bulbs. 

Starting-Motor Faults. If the motor does not rotate, the battery 
may be discharged. In case the engine has been overhauled just 
before, main bearings may have been put up so tight that the starting 
motor has not sufficient power to turn it over. The starting switch 
may not be making good contact, the motor brushes may not be 


ELECTRICAL EQUIPMENT 


427 


bearing properly on the commutator, or the battery terminals may 
not be tight. If the starting motor rotates but does not crank the 
engine, the over-running clutch may not be running properly or 
the engaging gears do not mesh. When the starting motor cranks the 
engine a few turns and stops, the battery is almost discharged. Unless 
the engine starts after the first few revolutions, do not continue to run 



Fig. 288. Diagram of Layout for Testing Gray & Davis Generator 
Courtesy of Gray & Davis, Boston, Massachusetts 


the starting motor, as it will exhaust the battery yery quickly. 
Look for causes of engine trouble—lack of gasoline, ignition circuit 
open, or the like. 

Gray & Davis Service Tests. Garages caring for fifty or more 
cars find it profitable to install the equipment to carry out the neces¬ 
sary tests of electrical apparatus instead of referring every case that is 
beyond the ordinary requirements to the manufacturer or to one of 
its service stations. The makers recommend for testing generators 
and motors when removed from the car, the following apparatus: 

































































428 


ELECTRICAL EQUIPMENT 


(1) One g-h.p. electric motor with variable speed rheostat (direct current) 
giving a speed range of 600 to 1800 r.p.m. This is where only one machine is to be 
tested at a time; for running several from a countershaft, a 1- to 2-h.p. motor is 
necessary. (2) Three motor pulleys, 2, 3, and 7| inches in diameter, respectively, 
and three generator pulleys, 21, 3, and 5 inches in diameter. (3) Adjustable 
bases for holding generators. (These can be obtained from Gray & Davis.) 
(4) Portable voltmeter with a 15-volt scale. The instrument described for 
general testing will fill this requirement as well. (5) Ammeter with a charge and 
discharge reading to 25 amperes, i.e., 25—0—25. (6) One tachometer, or rev¬ 

olution counter. (7) Four Ediswan base sockets and three 15-c.p. 7-volt lamps. 
(8) One single-pole single-throw switch and two single-pole double-throw switches, 
all of 15-ampere capacity. (9) One 80-ampere-hour 6-volt storage battery. 
(10) Sufficient No. 10 flexible cable for making the necessary connections. 

The above apparatus is more particularly for the generator tests. 
For making motor tests, the following are necessary: 

(1) Ammeter reading to 400 amperes. (2) One spring scale reading to 20 
pounds. (3) One single-pole single-throw switch of 200-ampere capacity. 
(4) Steel clamp and base for motor. (5) One 6-inch flanged iron pulley. 
(6) Sufficient No. 1 flexible cable for connections. 

Generator Test Chart, In order to enable the tester to check the 
performance of the generator, the test chart, Table III, has been 
supplied. The method of mounting the §-h.p. motor, switches, 
instruments, rheostat, and storage battery is shown in Fig. 288, 
while the wiring diagram showing the method of connecting up the 
various units is illustrated in Fig. 289. Referring to the test chart, 
Table III, column 1 gives the types of generators manufactured by 
Gray & Davis. To determine the type number, it is necessary to 
note only the first three numbers on the name plate. For instance, 
2221541 indicates type 222, machine 1541. This applies to all 
machines of this make turned out since September, 1915. 

Column 2 shows the amount of current required to run the gen¬ 
erator as a motor, or to ‘"motorize” it. To take this reading, the 
posts AF and F-1 should be connected together with a copper wire 
and the wire from the battery connected to the post A. The ampere 
reading and the speed should be within 10 per cent of the figures 
given in column 2. If not, remove the regulator and repeat the test, 
column 3 showing the proper speed. If the armature is shorted it 
will take excessive current, the ammeter needle will fluctuate, and 
the speed will be below normal. If the current is excessive but 
steady and the speed is high, it will show a defect in the fields or 
the field connections, as indicated in succeeding paragraphs. 


ELECTRICAL EQUIPMENT 


429 


TABLE III 


Test Chart for Gray & Davis Generators 


Information for Service Stations 


1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

Type of 
Gener¬ 
ator 

Running Light 
AS A Motor at 
6 Volts 

Low 
Speed 
Reading 
10 Amp. 

Amperes Charge 
TO Battery with 
7i Amp. Lamp Load 

Shunt Field 
Current 

AT 6 Volts 

Output of 
Dynamo with 

75 Amp. Load 

Amp. 

Speed 

(r.p.m.) 

Max. 

Min. 

Max. 

Min. 

Max. 

Min. 

Chandler S 

3 

320 

750 

4.5 

1 

1 

32 

1 

09 

11 

8.5 

Paige S 

3 

320 

750 

6 

1 

1 

32 

1 

09 

12 

8.5 

Chalmers T 

3 

650 

1300 

4.5 

1 

1 

30 

1 

04 

11 

8.5 

Metz T 

3 

650 

1300 

4.5 

1 

1 

30 

1. 

04 

11 

8.5 

M.G.9 

10 

700 { 

8 Amp. 
1575 

} 4.5 

1 

1 

20 


96 

11 

8.5 

300 

10 

700 { 

8 Amp. 
1575 

j 4.5 

1 

1 

20 


96 

11 

8.5 

301 

10 

700 { 

8 Amp. 
1575 

j 4.5 

1 

1 

20 


96 

11 

8.5 

210 

3 

320 

750 

6 

1 

1 

32 

1 

09 

12 

8.5 

211 

3 

650 

1300 

4.5 

1 

1 

30 

1 

04 

11 

1 8.5 

212 

3 

650 

1300 

6 

1 

1 

30 

1 

04 

12 

8.5 

213 

3 

650 

1300 

6 

1 

1 

30 

1 

04 

12 

8.5 

214 

3 

650 

1300 

6 

1 

1 

30 

1 

04 

12 

8.5 

216 

3 

650 

1300 

6 

1 

1 

30 

1 

04 

12 

8.5 

217 

3 

650 

1300 

6 

1 

1 

30 

1 

04 

12 

8.5 

218 

3 

650 

1300 

6 

1 

1 

30 

1 

04 

12 

8.5 

219 

3 

650 

1300 

4.5 

1 

1 

30 

1 

04 

11 

8.5 

220 

3 

300 

600 

4.5 

1 

1 

02 


77 

11 

8.5 

222 

3 

335 

700 

4.5 

1 

1 

02 


77 

11 

8.5 

223 

3 

335 

700 

6 

1 

1 

02 


77 

12 

8.5 

224 

3 

300 

600 

6 

1 

1 

02 


77 

12 

8.5 

225 

3 

300 

600 

4.5 

1 

1 

02 


77 

11 

8.5 

226 

3 

335 

700 

4.5 

1 

1 

02 


77 

11 

8.5 

227 

3 

650 

1300 

6 

1 

1 

30 

1 

04 

12 

8.5 

228 

3 

650 

1300 

4.5 

1 

1 

30 

1 

04 

11 

8.5 

229 

3 

335 

700 

4.5 

1 

1 

02 


77 

11 

8.5 

230 

3 

335 

700 

6 

1 

1 

02 


77 

12 

8.5 

231 

3 

335 

700 

6 

1 

1 

02 


77 

12 

8.5 

232 

3 

300 

600 

6 

1 

1 

02 


77 

12 

8.5 

233 

3 

335 

700 

4.5 

1 

1 

02 


77 

11 

8.5 

234 

3 

650 

1300 

4.5 

1 

1 

30 

1 

04 

11 

8.5 

235 

3 

150 

1300 

4.5 

1 

1 

30 

1 

04 

11 

8.5 

236 

3 

300 

600 

6 

1 

1 

02 


77 

11 

8.5 

237 

3 

320 

750 

4.5 

1 

1 

.32 

1 

.09 

12 

8.5 

238 

3 

650 

1300 

4.5 

1 

2 

.60 

2 

08 

11 

8.5 

239 

3 

650 

1300 

4.5 

1 

2 

.60 

2 

08 

11 

8.5 

240 

3 

335 

700 

4.5 

1 

2 

04 

1 

54 

11 

8.5 

241 

3 

335 

700 

4.5 

1 

2 

.04 

1 

54 

11 

8.5 

242 

3 

335 

700 

4.5 

1 

2 

04 

1 

54 

11 

8.5 

243 

3 

335 

700 

4.5 

1 

1 

02 


.77 

11 

8.5 

244 

3 

335 

700 

4.5 

1 

2 

04 

1 

54 

11 

8.5 

245 

3 

300 

600 

4.5 

1 

2 

04 

1 

54 

11 

8.5 

246 

3 

335 

700 

6 

1 

2 

04 

1 

.54 

12 

8.5 

247 

3 

300 

600 

6 

1 

2 

04 

1 

54 

12 

8.5 

248 

3 

300 

600 

4.5 

1 

2 

04 

1 

54 

11 

8.5 

249 

3 

335 

700 

4.5 

1 

2 

04 

1 

54 

11 

8.5 

250 

3 

335 

700 

4.5 

1 

2 

30 

2 

.04 

11 

8.5 

251 

3 

335 

700 

4.5 

1 

2 

30 

2 

04 

11 

8.5 

252 

3 

335 

700 

4.5 

1 

2 

30 

2 

04 

11 

8.5 

253 

3 

300 

600 

4.5 

1 

2 

30 

2 

.04 

11 

8.5 

254 

3 

335 

700 

6 

1 

2 

30 

2 

04 

12 

8.5 

255 

3 

300 

600 

6 

1 

2 

.30 

2 

.04 

12 

8.5 

256 

3 

300 

600 

4.5 

1 

2 

.30 

2 

.04 

11 

8.5 

257 

3 

335 

700 

4.5 

1 

2 

.30 

2 

.04 

11 

8.5 

258 

3 

335 

700 

4.5 

1 

2 

.30 

2 

.04 

11 

8.5 

259 

3 

300 

600 

6 

1 

2 

.30 

2 

.04 

12 

8.5 

260 

3 

335 

700 

4.5 

1 

1 

.02 


.77 

11 

8.5 

261 

3 

300 

600 

6 

1 

2 

.30 

2 

.04 

12 

8.5 

262 

3 

300 

600 

6 

1 

2 

.30 

2 

.04 

12 

8.5 








































430 


ELECTRICAL EQUIPMENT 


Column 4 affords a check on other defects in the machine. To 
take this reading, connect posts A F and F-1 together in order to give 
full field current, place machine on test bench, and run with belt. Speed 
the machine up until the ammeter indicates 10 amperes with the 
three I5-c.p. lamps in circuit and the battery testing 1.250 or over 
with the hydrometer. Take a reading of the speed. This should not 
be higher than that given in column 4. A higher reading will indicate 

defective fields, a high- 
resistance armature, pole 
pieces loose in frame, 
slight short-circuit in 
armature, defective 
brush or brush contact 
at commutator, or dirty 
commutator. 

The purpose of col¬ 
umns 5 and 6 is to check 
the action of the regu¬ 
lator. To take this read¬ 
ing, turn on the three 
15-c.p. lamps, giving a 
load of 7| amperes, and 
observe the amount of 
current passing into the 
battery with the amme¬ 
ter switch in position 2. 
The reading should be 
within the limits shown 
in columns 5 and 6. 

Columns 7 and 8 
show the current taken 
by the field coils. Connect one side of the battery to the frame of 
the generator and the other side through the ammeter to terminal F, 
The reading should not be greater than column 7 or less than 
column 8. Repeat the test at terminal F-1. A high reading will 
show a short-circuit, and a low reading will show a poor connection 
or a high resistance in the field. No reading at all will indicate an 
open circuit in the field. 


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Baff'ery 

Fig. 289. Wiring Diagram for Gray & Davis 
Dynamo and Regulator 




























































ELECTRICAL EQUIPMENT 


431 


TABLE IV 

Test Chart for Gray & Davis Starting Motor 


1 

2 

3 

4 

5 

6 

7 

8 

9 

Type 

OF 

Motor 

Running Free Reading 

Minimum 

Gear 

1| Lb. Torque Read¬ 
ing AT 5i Volts 





Brush 

Reduction 



Max. 

Amp. 

Speed 

3 

Volts 

Speed 

5.5 

Volts 

Speed 

6 

Volts 

Pressure 

(lb.) 

IN Gear 
Housing 

Amperes 

Speed 

(r.p.m.) 

100 

35 

3500 

6600 

7000 

3| 

None 

137 

2400 

101 

35 

3500 

6600 

7000 

3^ 

49-14 

137 

2400 

102 

35 

3500 

6600 

7000 

3| 

47-16 

137 

2400 

103 

35 

3500 

6600 

7000 

3^ 

50-13 

137 

2400 

104 

35 

3500 

6600 

7000 

3| 

50-13 

137 

2400 

105 

35 

3500 

6600 

7000 

31 

84-12 

137 

2400 

106 

35 

3500 

6600 

7000 

3^ 

51-12 

137 

2400 

107 

35 

3500 

6600 

7000 

31 

51-12 

137 

2400 

108 

35 

3500 

6600 

7000 

3i 

50-13 

137 

2400 

109 

35 

3500 

6600 

7000 

3| 

50-13 

137 

2400 

110 

35 

1900 

3800 

4100 

31 

51-24 

98 

1980 

113 

35 

3500 

6600 

7000 

31 

50-13 

137 

2400 

115 

35 

3500 

6600 

7000 


50-13 

137 

2400 

116 

35 

3500 

6600 

7000 

3| 

51-12 

137 

2400 

117 

35 

3500 

6600 

7000 

31 

51-12 

137 - 

2400 

118 

35 

3500 

6600 

7000 

3^ 

50-13 

137 

2400 

119 

35 

2200 

4500 

5000 

2i 

None 

100 

1660 

120 

35 

2200 

4500 

5000 

2i 

Direct 

100 

1660 

121 

35 

2200 

4500 

5000 

21 

Direct 

100 

1660 

' 122 

35 

1900 

3800 

4100 

3^ 

Direct 

98 

1980 

1 123 

35 

3500 

6600 

7000 

3| 

49-14 

137 

2400 

■ 124 

35 

3500 

6600 

7000 

3^ 

51-12 

137 

2400 

125 

35 

3500 

6600 

7000 

31 

50-13 

137 

2400 

126 

35 

2200 

4500 

5000 

2i 

Direct 

100 

1660 

127 

35 

2200 

4500 

5000 

2i 

Direct 

100 

1660 

128 

35 

3500 

6600 

7000 

3i 

51-12 

137 

2400 

129 

35 

2200 

4500 

5000 

2i 

54-12 

100 

1660 

130 

35 

2200 

4500 

5000 

21 

Direct 

100 

1660 

131 

35 

2200 

4500 

5000 

21 

Direct 

100 

1660 

132 

35 

2200 

4500 

5000 

21 

Direct 

100 

1660 

133 

35 

3500 

6600 

7000 

3i 

50-13 

137 

2400 

134 

35 

3500 

6600 

7000 

3^ 

50-13 

137 

2400 

135 

35 

3500 

6600 

7000 

31 

49-14 

137 

2400 

136 

35 

3500 

6600 

7000 

H 

49-14 

137 

2400 

137 

35 

3500 

6600 

7000 

31 

50-13 

137 

2400 

138 

35 

2230 

4500 

5000 

21 

Direct 

100 

1660 

139 

35 

2230 

4500 

5000 

2i 

Direct 

100 

1660 

140 

35 

2230 

4500 

5000 

2i 

Direct 

100 

1660 

141 

35 

1900 

3800 

4100 

3| 

Direct 

98 

1980 

142 

35 

\1900 

3800 

4100 

1 - 

3^ 

51-24 

98 

1980 


Columns 9 and 10 show the current output for which the gener¬ 
ator is set at the factory. To test this, place the ammeter switch in 
position 1 and with the three 15-c.p. lamps turned on speed the 
machine above 1750 r.p.m. If the reading does not fall within 










































432 ELECTRICAL EQUIPMENT 

the limits given, adjust the regulator in accordance with instructions 
given below. 

Starting-Motor Test Chart. Table IV is provided for reference in 
cases where the motor trouble is of such a nature that it cannot be 
located except by a test, i.e., in the windings. Column 1 gives the 
types of starting motors, which may be identified in manner the same 
as the generators. The type number covers the motor and the speed 
reducer. 

Column 2 shows the current required to run the motor free. 
The reading should not vary by more than 25 per cent from the figures 
given. A high reading will indicate tight bearings, short-circuited 
armature, or field. 

Columns 3, 4, and 5 show the speed when running light with 
current at 3 volts, 5| volts, and 6 volts. The test should be made 
with either two or three cells of the battery. A low-speed reading 
with normal current will indicate loose connections, poor brush con¬ 
tact, dirty commutator, or high resistance in armature. A high¬ 
speed reading will indicate a short-circuit in the field windings. 

Column 6 gives the spring pressure on the brushes.’ Where the 
brushes show a tendency to spark, this brush pressure should be 
checked. This reading is taken with a small spring scale hooked on 
to the brush screw. Read the number of pounds required to just 
lift the brush from the commutator. The reading should not be less 
than the figures given in column 6. Column 7 gives the reduction 
between the starting-motor shaft and the countershaft which carries 
the sliding gear. 

Columns 8 and 9 are readings showing whether or not the motor 
is capable of delivering its rated power on normal current consump¬ 
tion and at normal speed. The reading is taken by putting on the 
shaft a load requiring a turning power of 1| pounds at a 1-foot radius. 
To take this reading the flanged pulley, spring scale, and a cord are 
employed in the manner shown in Fig. 290. The reading on the scale 
corresponding to IJ foot-pounds will be 6 pounds. Thus: foot¬ 

pounds times 12 inches equals 18 inch-pounds, which divided by 3 
inches (radius of pulley) gives 6 pounds (scale reading). 

To take the reading, close the switch and put just enough tension 
on the cord A to make the scale read 6 pounds and, holding this 
steady, read volts, amperes, and speed. The speed given in column 9 


ELECTRICAL EQUIPMENT 


433 


is taken at 5f volts, which is what would be obtained with a battery 
showing 1,250 or over on the hydrometer test. A lower voltage will 
cause a lower speed reading. In the majority of cases, tests made with 
the motor running free will show any defects, but in case these tests 
do not reveal any trouble and the motor still fails to operate satis¬ 
factorily, the tests for which the proper figures are given in columns 8 
and 9 should be carried out. 

To Adjust Cut-Out. The contact points should close to permit 
the battery to charge at 6 to 6| volts; they should open the circuit 
between the battery and the generator on a discharge of J to 2 



Fig. 290. Set-Up for Testing Power of Motor 
Courtesy of Gray & Davis, Boston, Massachusetts 


amperes. To test the cut-out, connect the voltmeter across the gener¬ 
ator brushes or have the voltmeter switch in position 1, Fig. 289. 
Gradually speed up the generator and observe the voltmeter to 
determine the closing voltage. The closing voltage is the reading 
on the voltmeter at the instant that the cut-out points come together. 
Adjust the cut-out spring to bring the closing voltage within the limits 
given above. With the lamps turned off and the ammeter switch in 
position 1, slow the machine down and observe the ammeter reading 
when the cut-out points open. Adjust the cut-out spring to make this 
reading fall within the above limits. In case a satisfactory result is 









































































434 


ELECTRICAL EQUIPMENT 


not obtainable after several attempts at adjusting the spring, check 
the air-gap distances, as given below. Correct these and test again. 

To Adjust Regulator. With all connections made and the 
ammeter switch in position 1, turn on the three 15-c.p. lamps and speed 
the machine up to above 1750 r.p.m. Open the upper set of points 
with the aid of a match or by using the finger. Adjust the lower set 
of points by the ammeter reading so as to bring it within the limits 
given in columns 9 and 10 of the generator test chart. Repeat the 
adjustment on the upper set, opening the lower set while the test is 
being made. Run the machine with both sets of points free and the 
reading should fall within the limits given in columns 9 and 10. 

HEINZE=SPRINQFIELD SYSTEM 

Six=Volt; Two=Unit; SingIe=Wire 

Generator. The generator is of the multipolar shunt-wound 
type (four poles) with brushes spaced 90 degrees apart, bringing both 
on the left side of the commutator to make them more accessible. 
The negative, or lower, brush of the generator, Fig. 291, is grounded 
to the brush holder, which, in turn, is grounded on the generator 
brush head. From the positive, or upper, brush a wire runs to the 
terminal GEN. BR.+ of the regulator and cut-out. Fig. 292. 
From this terminal, the charging circuit leads to the cut-out contacts 
and through the latter and the series winding to the terminal 
BAT+ of the regulator cut-out. As the negative brush of the 
generator is grounded, the negative terminal of the battery and one 
side of all the lights are grounded. One end of the generator shunt 
field is grounded inside to the generator frame. The other end comes 
out through the hole provided for it in the brush head, runs to the 
terminal FLD of the regulator cut-out, and thence to the contacts 
of the current regulator if they are closed, or through a resistance if 
they are open. 

Starting Motor. The starting motor is of the four-pole series- 
wound type with the brushes at 90 degrees apart, as on the generator. 
The positive brush is on top of the commutator and carries a terminal 
to which is connected the starting cable. The lead from the negative 
brush divides, part of the current passing around two of the four poles 
to the ground, while the other part passes through the other two poles 
to the ground connection. On starting motors bearing serial numbers 


ELECTRICAL EQUIPMENT 


435 















































































































































436 


ELECTRICAL EQUIPMENT 


below 5471, the grounded ends of the series fields were soldered to the 
pole pieces, but this has since been altered by securing the two ends 
of the series field to a ground lead, which, in turn, is secured to the 
bottom of the motor brush head by means of a hexagonal nut and 
lock washer. 

While the system is of the two-unit type and the units are inde¬ 
pendent of each other electrically, they are combined mechanically 
by making the rear heads of both in one casting. The starting motor is 
the upper of the two units, the lighting generator being placed directly 
beneath it. This refers to the set supplied for installation on the Ford. 



Fig. 292. Heinze-Springfield Current Regulator and Battery Cut-Out 


Method of Operation. Drive is by means of a silent chain directly 
to the sprocket on the generator shaft. In addition to the sprocket 
in question, the generator shaft carries also a large gear adapted to 
mesh with the small pinion on the shaft of the Bendix drive mounted 
on the shaft of the starting motor. When the starting motor rotates, 
the Bendix pinion automatically engages the gear on the generator 
shaft and drives to the engine through the silent chain, the engagement 
being broken as soon as the engine turns over under its own power. 

Regulation. Voltage Regulator and Resistance. The current 
regulator is combined with the battery cut-out and the combined unit 























































ELECTRICAL EQUIPMENT 


437 


is mounted directly on the starting motor, Fig. 292. The regulator 
side of the relay consists of two contacts B, which are normally held 
together by spring tension so that the charging current does not 
exceed 10 to 12 amperes. When the voltage rises above a certain 
value owing to the increased speed of the engine, the regulator arma¬ 
ture is drawn down, separating the contacts, and the current must 
then pass through the resistance unit shown beneath the coil. This 
keeps the charging current down to the value mentioned. 

On the battery cut-out side, the relay consists of two contacts A, 
which are normally held apart by spring tension when the engine is 
not running or is running too slowly to charge the battery. As soon 
as it is running fast enough to generate sufficient voltage to overcome 
that of the storage battery, the regulator armature is drawn down, 
closing the contacts. This occurs at an engine speed equivalent to 
about 6 miles per hour, at or above which the battery is always charg¬ 
ing. When the speed decreases to below this point, the pull on the 
armature is not sufficient to hold it down, and the contacts are 
separated by the spring C. 

Starting Switch. The starting switch is a combination dash 
switch designed to control the starting, lighting, and ignition. In 
the Ford set, the current for starting and lighting is furnished by the 
battery, while the current for ignition comes from the Ford magneto. 
Starting is accomplished by depressing the button in the center of 
the switch, while the lights are controlled by rotating the switch 
lever. By rotating the switch lever, the ignition rotor connects the 
contacts M and C, Fig. 399, in the IGN. ON position and allows 
current to flow from the magneto through the switeh, coil, and plug 
connections. The lighting rotor of the switch is always supplied with 
current from the battery through a sliding contact of the wiping 
type. When at the “Lights Dim” position, the current passes through 
the dimming resistance, the ignition remaining undisturbed by this 
change. The switch is designed to lock both the starting contact 
and the lighting and ignition lever in the IGN. OFF “Lights 
Dim” position for parking at night, and in the OFF position for 
the daytime. 

Instruments and Protective Devices. Unless specially ordered, an 
ammeter is not provided with the system designed for the Ford but 
may be had at an extra cost in the form of a combination panel 


438 


ELECTRICAL EQUIPMENT 


carrying the switch, the ammeter, and a dash light. The regulator and 
the cut-out serve to protect the generator and the battery, respectively. 

Wiring Diagram. As installed on the Ford, including an amme¬ 
ter and dash lamp as just mentioned, the details of the wiring are 
shown in Fig. 401. The negative side of both the generator and the 
starting motor are grounded, the connection being split in the latter 
case and two grounds made. The negative side of the battery and 
one side of all the lamps and the horn as well are accordingly grounded. 
As ignition current is supplied by the magneto, the only connection 
of the ignition system with the lighting and starting system is at the 
combination switch. The charging current from the generator passes 
through the regulator (lower set of contacts) and when the engine is 
running at a speed equivalent to 6 miles an hour or more, the arma¬ 
ture of the cut-out is pulled down and the upper set of contacts closes. 
This sends the charging current through the battery. Should the car 
be driven at a speed which causes the output of the generator to 
exceed 10 to 12 amperes, the regulator armature is attracted and the 
regulator contacts separate, thus shunting the current through a 
resistance which immediately serves to decrease the excitation of the 
generator fields and correspondingly reduces the current output of 
the latter. When the speed of the engine drops below a point where the 
voltage generated is insufficient to charge the battery, the cut-out 
contacts are separated by the spring, as the pull of the magnet is then 
not strong enough to hold it down. The lights are supplied directly 
from the battery, as will be noted, the diagram making clear the vari¬ 
ous positions of the rotating switch to give the different combinations 
available. The various connections and their significance will be 
clear upon comparing this with other and similar wiring diagrams. 

Instructions. Failure of the starting motor to operate is usually 
caused by lack of current iir the storage battery, although this fault 
may be due to several causes, acting either separately or together. 
Lack of charge in the battery is usually caused by over-frequent use of 
the starting system with but little driving between, so that the gen¬ 
erator is not given an opportunity to charge the battery. Other 
causes of failure are treated under Starting and Lighting Storage 
Batteries, in another section. 

Starting Motor. The starting motor may not operate because of 
internal trouble. This may take the form of an open- or short- 



ELECTRICAL EQUIPMENT 


439 


circuited armature or field, dirty commutator, insufficient tension on 
brushes, brushes not bearing on commutator, or grounded brush 
holders, armature, or field. Of these various causes of failure, the 
first is liable to be the most rare. For their correction see the various 
sections on testing for grounds and short-circuits with the aid of the 
ammeter also on care of commutator and brushes, given in connection 
with the description of other systems. The attention required 
is identical in practically every case and, where the brushes and 
the commutator are concerned, does not vary even in detail on the 
different systems. 

Bendix Drive. Failure of the Bendix drive to operate properly 
may be due to lubricating the screw shaft, on which no oil or grease is 
necessary, since it will work better without it. Putting oil on this 
shaft makes impossible the ‘Tunning start”, which is the great advan¬ 
tage of the Bendix drive, i.e., the starting motor should almost 
instantly attain a high speed the moment the current is turned on, 
but the Bendix pinion will not move for a perceptible interval. When 
the Bendix pinion does move, the starting motor is running so fast 
that, at the moment the pinion engages suddenly, owing to the action 
of the spring, the engine is turned over the first compression very 
much easier than if the motor had to start nuder load. 

Generator. Trouble in the generator will usually be manifested 
by the failure of the machine to generate a terminal voltage. The 
first warning would be the absence of any reading at the ammeter 
when the generator should be charging, the engine then running at a 
speed equivalent to 6 miles an hour, or over. If no ammeter is 
employed, the discharged condition of the battery may be traced 
either to the generator or to failure to drive The car sufficiently 
during the daytime and between starts to keep the battery charged. 
If, upon test with the hydrometer, the battery indicates rapid recu¬ 
peration after the engine has been running for 15 to 30 minutes, the 
gen erator is not at fault. Should the battery specific-gravity test not 
show any improvement after running 30 minutes, the fault may be 
either in the generator or in the regulator cut-out. As is the case 
with the starting motor, defects in the generator may take the form 
of a dirty commutator, badly worn brushes, insufficient tension of 
brush springs to keep the brushes bearing on the commutator; the 
positive brush may be grounded; or there may be open-circuits or 


440 


ELECTRICAL EQUIPMENT 


grounds, or short-circuits or grounds in the field or armature. In any 
case, the attention necessary will be the same as that already outlined 
for similar faults on other systems. 

Regulator and Cut-Out. The regulator and cut-out consist of a 
single electromagnet with a split core on which there are two windings. 
The primary is in series with main charging circuit and the sec¬ 
ondary is shunted across the motor brushes. If the generator is at fault, 
the battery cut-out naturally will not work, as there will be no voltage 
to operate it; but there will be times when the generator is working all 
right and the regulator is at fault, although it may be difficult at 
first sight to make sure which is the cause of the trouble. To deter¬ 
mine this, with the engine running at a speed equivalent to 6 miles an 
hour or more, press the battery cut-out contacts together with the 
fingers. If the ammeter then shows a charge reading, and there is no 
dash ammeter, a weight may be placed on the cut-out armature to 
keep the contacts together for 30 minutes or so, and if the battery 
then shows that it is charging, the cut-out and not the generator 
is at fault. If, with the cut-out contacts thus held together, 
there is no sign of charging the battery, the generator is the cause 
of the trouble. 

To adjust the regulator and cut-out, first adjust the regulator 
side, as the cut-out is dependent upon the regulator adjustment. 
Before starting the engine, remove the regulator and the cut-out 
cover, then remove the wire to the terminal “BAT-f ” and insert 
an ammeter in the charging circuit at this point, though if there 
be an ammeter on the dash, it may be used. Start the engine and run 
it very slowly. See that the regulator contacts are together. Fig. 292. 
At a speed equivalent to 6 miles an hour or over, the cut-out contacts 
A should close, and with the contacts at B closed, the ammeter 
should show a reading of 4 amperes. If contacts A do not close at 
this point, there may be too much tension on the spring, which may 
be remedied by bending the spring-holding support upward at C. 
Should the ammeter reading go above 10 to 12 amperes as the speed 
increases, this is due to the contacts B of the regulator not opening as 
they should. The tension of the armature spring of the regulator 
should then be lessened by bending the spring-holding support slightly 
upward at D. Note very carefully as the engine speed is decreased 
that there is enough spring tension on the cut-out armature to open 


ELECTRICAL EQUIPMENT 


441 


the contacts A when the relay is demagnetized, due to the voltage 
of the battery exceeding that of the generator. 

Trouble in the regulator and cut-out will manifest itself in two 
ways—insufficient charging current or no charging current reaching 
the battery and too much current at the higher car speeds. It may be 
due to several causes, acting either separately or collectively—the 
armatures springs may be out of adjustment; the current or voltage 
windings may be short-circuited, open, or grounded; the two sets of 
contacts may be dirty; or the resistance unit may be open. If the 
ammeter reading fluctuates though the engine speed remains constant, 
it is an indication of dirty contacts. They should be trued up with a 
file. If the regulator has failed, the current may have attained a 
value of 30 to 40 amperes and caused the contacts to fuse together. 
Separate and file clean. 


























U-S-L-MOTOR-GENERATOR DISASSEMBLED WITH INSTRUMENT BOARD ABOVE 

Courtesy of U. S. Light and Heat Corporation, Niagara Falls, New York 












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ELECTRICAL EQUIPMENT FOR 

GASOLINE CARS 

PART VI 


ELECTRIC STARTING AND LIGHTING 
S Y STEMS —(Continued) 

PRACTICAL ANALYSIS OF TYPES— (Continued) 

LEECE=NEVILLE SYSTEM 
Six=Volt; Two=Unit; Two-Wire 

Generator. Standard shunt-wound bipolar type, combined 
with ignition timer and distributor driven by a worm gear on the 
armature shaft. The generator is mounted on the left side of the 
engine and is driven by the pump shaft (Haynes 1913 installation, 
and subsequent models to date). 

It differs from the standard shunt-wound machine in that the 
shunt field is connected to the regulating third brush. This brush 
collects current from the commutator and excites the field, so that a 
strong shunt field is provided at comparatively low speeds. As the 
speed increases, the voltage supplied to the shunt field decreases, 
even though the total voltage between the main brushes may have 
increased. This weakens the field and prevents the output of the 
generator from increasing with the increased speed. At higher speeds 
it acts somewhat similarly to a bucking-coil winding in that it further 
weakens the field and causes the generator output to decrease still 
more. The closer the third brush is set to the main brush just above, 
the greater will be the output of the machine; moving it away from 
the main brush decreases the output. 

Regulation. Generators of the 1915 and 1916 models are con¬ 
trolled by armature reaction through a third brush, the field coils 
receiving their exciting current from the armature through this 
brush. The position of the latter on the commutator is shown at 
B, Fig. 293. A slight rotation of this brush relative to the com- 




444 


ELECTRICAL EQUIPMENT 


mutator changes tlie electrical output of the machine. As adjusted 
at the factory this brush is set to give a maximum output of 15 

amperes at 7^ volts. (All generators 
for 6-volt systems are wound to pro¬ 
duce an e.m.f. of volts, or there¬ 
about, in order that the voltage 
of the generator may exceed that of 
the battery when the latter is fully 
charged. The e.m.f. of generators 
for 12-volt and 24-volt systems also 
exceeds that of their batteries in 
about the same proportion. Other¬ 
wise, the generator would not be able 
to force current through the battery.) 

Starting Motor. , The motor is 
of the bipolar series-wound type 
driving the engine through a roller 
chain and an over-running clutch. 

Instruments. An indicating 
type of battery cut-out is employed, 
thus combining the functions of the 
cut-out and ammeter in one device. The details of this device are 
shown in Fig. 294. 0 is the winding or coil of the electromagnet 

of which the U-shaped bar 
8 forms the magnetic circuit. 
At Jj. is the pivoted armature, 
normally held in the OFF 
position as shown by a spring, 
when no current is passing, 
and adapted to be drawn 
against the pole pieces of 
the magnet when the latter 
is excited by the charging 
current. As the two-wire sys¬ 
tem is employed, the cut-out 
breaks both sides of the battery-charging circuit and it is provided 
with six current-carrying contacts on each of the sides of the circuit. 
Four of these, which carry most of the current, are copper to bronze, 



Fig. 293. Diagram of Arrangement of 
Brushes on Leece-Neville 
6-Volt Generator 



Fig. 294. Details of Leece-Neville Indicator 


















































ELECTRICAL EQUIPMENT 


445 


while those that take the spark in breaking the circuit are cophite to iron 
and are actuated by a spring. The indicating target 16 is held in the 
OFF position by the spring 19 when no current is passing, and 
this reading appears in the opening of the panel on the cover. 
When the generator starts and the cut-out closes, the target is 
moved to bring the word CHARGING in the opening. The 
same panel also carries the three-way lighting switch controlled 
by buttons. The central button closes the circuit to the head¬ 
lights and tail lights in the usual manner, while the upper button 
throws the headlights in series-parallel connection. As this doubles 
the resistance, it halves the voltage passing through the lamps, and 
they, accordingly, burn dimly. The lower button controls the cowl 
light over the instruments on the dash. 

Wiring Diagram. Fig. 295 illustrates the Haynes 1915 installa¬ 
tion. While two wires are employed for connecting all the appara¬ 
tus, it will be noted that the storage battery and the dry-cell battery 
are grounded by a common ground connection. This is to permit 
using current from the storage battery for ignition, the correspond¬ 
ing ground to complete the circuit being noted at the ignition coil, 
close to the distributor. The connections G and B on the panel 
board are those of the generator and the battery to the indicating 
battery cut-out, the connections of three lighting switches being 
shown just to the right. In Fig. 296 is shown the Leece-Neville 
installation in White cars. 

Instructions. Never run the engine when the generator is dis¬ 
connected from the battery unless the generator is short-circuited, 
as otherwise it will be burned out in a very short time. This applies 
to all lighting generators except those protected by a fuse in the 
field circuit, in which case the fuse will be blown. The Leece-Neville 
generator can be short-circuited by taking a small piece of bare 
copper wire and connecting the two brush holders together with it. 
Instructions for short-circuiting other makes are given in connec¬ 
tion with the corresponding descriptions. 

Later models of the Leece-Neville generator are provided with a 
circuit-breaker. On the Haynes 12-cylinder models, this is mounted 
on top of the generator, while in some cases it is combined with the 
ammeter on the dash. To protect the generator and battery, there 
is a 5-ampere cartridge fuse under the cover of this circuit-breaker. 


a/tod^o 


1 


416 


ELECTRICAL EQUIPMENT 


«/^y7 7/iU. 


jo/e Jwv 

h^/t/007 C/A^X 

SAz/^^s/y ^ ^yut/3i/e 




Fig. 295. Wiring Diagram for Leece-Neville System on Haynes Light Six 






























































































ELECTRICAL EQUIPMENT 


447 


When this fuse blows out, both the generator and the circuit-breaker 
become inoperative. Any one of the following conditions may cause 




Fig. 297. Wiring Diagram of Generator and Circuit-Breaker Circuits for Leece-Neville System 

Courtesy of The Seece-Neville Company, Cleveland, Ohio 

this fuse to blow out: loose or corroded connections at the battery; an 
open circuit in the wiring on the battery side of the cut-out; not 
sufficient water in the battery; output of the generator too high; 










































































































































448 


ELFXTHIC^AL EQUIPMENT 


allowin^^ the main l)nish directly above the third brush to stick in its 
holder; a loose connection at the point X 2 , Fig. 297; improper insula¬ 
tion between the wires Bi and B 2 in the connector plug, Fig. 297. 


By an open circuit is meant an actual break at a connector or a termi¬ 
nal, or in the wiring itself, while a loose connection signifies an inse¬ 
curely fastened terminal or wire, at a junction box, or at any other part 
of the system. If there is a short-circuit in the field winding of the 
generator, this also will cause the fuse to blow out. 

Testing the Field Winding. While a short-circuit in the field 
winding of any generator is a rare fault, there are times when the 
trouble cannot be traced to any other part of the system. To test 
the Leece-Neville generator for this, connect the negative terminal of 
the portable testing ammeter to Fi, Fig. 297, while the positive termi¬ 
nal of the motor must be connected to the positive terminal of a 6-volt 
storage battery; the negative terminal of the battery is to be connected 
to the third brush when drawn from its holder. If the indication of 
the ammeter is above 4 amperes, there is a short-circuit in the field 
windings. In such a case, the generator should be returned to the 
manufacturers for repairs. 

With the engine running, the working of the generator should be 
inspected from time to time. In case there is excessive sparking or 
“arcing” between the brushes and the commutator, examine the con¬ 
nections at Fi and Ai and see that the screws are perfectly tight, 
as these screws sometimes work loose and are responsible for this arc¬ 
ing which is destructive to the commutator. The loosening of the 
connections at Fi and Ai will have no effect on the fuse; but if the 
connection at A 2 loosens, the fuse will burn out. When inspecting the 
operation of the generator, see that the brushes are making good even 
contact with the commutator, and wipe away all particles of dust and 
grit from around the brushes and their holders. With the engine 
stopped, see that the brushes move freely in their holders. This 
should always be done where a car has been laid up for some time 
(before starting the engine) as the brushes, through disuse, will have 
a tendency to stick. 

The fuse in the circuit-breaker has no effect whatever on the 
output of the generator, so that a larger fuse must not be inserted in 
case the generator is not delivering its rated output or more. The 
makers supply a 5-ampere fuse for this purpose, and if a fuse of 


ELECTRICAL EQUIPMENT 


449 


heavier capacity is employed, it will cause both the circuit-breaker 
and the generator so burn out. This will be the case also where a 
“jumper” is resorted to, i.e., a piece of wire or other metal bridging 
the fuse clips so that the fuse is cut out of the circuit. It must be 
borne in mind, however, that these fuses are more or less fragile and 
are likely to become damaged by careless handling. A fuse whose 
connections have been loosened up is likely to blow out on that 
account, so before inserting a fuse in the clips of the circuit, it should 
be examined to see that the ferrules on each end of the cartridge are 
perfectly tight. Where a good fuse has been inserted and it blows out, 
the cause should be ascertained before inserting another fuse. 

Regulating Brush. In case the generator output falls off as 
shown by its inability to keep the battery properly charged, the 
battery itself and all connections being in good condition, and a 
proper amount of day running being done to provide the necessary 
charging current, the trouble may be in the regulating brush of the 
generator. Test by inserting an ammeter, such as the Weston 
portable or any other good instrument with a scale reading to 30 
amperes, in the line between the generator and the battery. Run 
the engine at a speed corresponding to 20 miles per hour, at which 
rate the ammeter should record a current of approximately 15 
amperes. If the ammeter needle butts against the controlling pin 
at the left end of the scale instead of showing a reading, it indicates 
that the polarity is wrong, and the connections should be reversed. 
Should there be no current whatever, the needle will stay perfectly 
stationary except as influenced by vibration. If the ammeter shows 
a reading of less than 15 amperes, the current output of the gener¬ 
ator may be increased by loosening the set screw holding the third 
brush and rotating the brush slightly in the same direction as the 
rotation of the armature. This should be done with the generator 
running and the ammeter in circuit, noting the effect on the reading 
as the brush is moved. To decrease the output, it should be moved 
in the opposite direction until the proper reading is obtained, after 
which the brush must be sanded-in to a good fit on the commutator. 
It may sometimes occur that sufficient movement cannot be given 
the third brush without bringing it into contact with one of the 
main brushes. This must be avoided by loosening the two set 
screws E, Fig. 293, and moving the main brush holder away 


450 


ELECTRICAL EQUIPMENT 


from the third brush until there is no danger of their touching. 
After securing the desired adjustment, fasten the third brush in 
place again, stop the engine, and then reconnect the generator to the 
battery. Do not cut the ammeter out of the circuit while the gen¬ 
erator is running. 

To Adjust Third Brush. Before making any adjustment of the 
third brush when it is suspected that any trouble with the current 
supply is due to the generator, the output of the generator should be 
tested. On a car equipped with lamps totaling 250 candle power or 
more (this refers to White busses), the generator should produce 20 
amperes. Run the engine at a speed sufficient to drive the car 15 
o 16 miles per hour on direct drive and note the reading of the dash 
ammeter. In case the car has seen considerable service, it may be 
well to check the dash ammeter with the more accurate portable 
ammeter described in connection with other tests in previous and 
subsequent sections. Where the car lighting system totals 250 c.p. 
or over, and the ammeter reading shows more than four amperes above 
or below 20, the generator should be adjusted to give its rated capacity 
of 20 amperes—as every 15 c.p. less than 250 c.p. used on the car, 
lower the output of the generator by one ampere. By making the 
adjustments in this manner, the storage battery will be amply 
protected. 

Before making any generator adjustments, test the storage bat¬ 
tery with the hydrometer. Do not add any distilled water just pre¬ 
vious to making this test unless the level of electrolyte is right down to 
the plates so that sufficient liquid cannot be drawn into the hydrome¬ 
ter; in this case, add water and charge the battery for at least one hour 
before making the hydrometer test. If the specific gravity of the elec¬ 
trolyte is 1,250 or over, and the generator is found to be delivering less 

than the rated lamp load, no adjustment of the generator should 
be made. 

To increase the output of the generator, rotate the third brush 
in the direction of rotation of the armature; to decrease the output, 
move the brush against the direction of rotation. Adjustments 
should be made with the engine standing. Loosen the screw at the 
rear of the commutator housing shown at the point F, Fig. 293. 
This releases the third brush holder, and the brush may then be moved 
in the direction desired. It should be moved only a short distance. 


ELECTRICAL EQUIPMENT 


451 


and tlie generator then should be tested until the desired output is 
secured. In case the third brush should come in contact with the 
main brush above in the course of adjustment, it will be necessary to 
move the main brushes. To do this, loosen the two set screws E, 
Fig. 293, and move the main brush holder far enough away from 
the third brush so that there is no possibility of contact between them. 
When the desired location is found, sand-in the third brush to the com¬ 
mutator and also clean the commutator with a piece of worn sand¬ 
paper as described in the section oil Sanding-In the Brushes (Delco 
instructions); if it has been necessary to move the main brushes, they 
should be sanded-in also. The brush holder screws should be well 
tightened after making any adjustments to prevent any possibility of 
the vibration and jolting loosening them up and throwing the gener¬ 
ator out of adjustment again. 

Brush Replacements. Never replace any of the brushes on 
either the generator or starting motor with any but those supplied 
by the manufacturer of the system for this purpose. Motors and 
generators adapted for use on electric-lighting circuits are usually 
fitted with plain carbon brushes. These are not suitable for use on 
automobile generators or starting motors owing to their resistance 
being much higher. Due to the low voltage of electric apparatus 
on the automobile, special brushes of carbon combined with soft 
copper are usually employed. Brushes also differ greatly in hard¬ 
ness, and a harder brush than that for which the commutator is 
designed will be liable to score it badly besides producing a great deal 
of carbon dust, which is dangerous to the windings. This, of course, 
applies to all makes of apparatus and not merely to that under 
consideration. 

Generator or Motor Failure. For failure of the generator or of 
the starting motor, see instructions under Auto-Lite, Delco, and 
Gray & Davis, bearing in mind, however, that the system under 
consideration is of the two-wire type, so that in using the test lamp 
to locate short-circuits a connection to the frame or ground is not 
always necessary. The short-circuit may be between two adjacent 
wires of different circuits. Given properly installed wires and 
cables, there is less likelihood of short-circuits in the wiring of a two- 
wire system. Defective lamps will not infrequently prove to be the 
cause, as, in burning out, a lamp often becomes short-circuited. 


452 


ELECTRICAL EQUIPMENT 


NORTH EAST SYSTEM* 

Twe!ve=Volt, Sixteen=VoIt, or Twenty=Four=Volt; Single=Unit; Single^ 
Wire or Two=Wire, According to the Installation 

Dynamotor. The dynamotor is of the four-pole type, with both 
windings connected to the same commutator. It is designed for 
installation either with silent-chain drive—as on the Dodge, Fig. 298, 
in which case the drive is direct either as a generator or as a motor 
or with a special reducing gear and clutch for driving from the 
pump or magneto shaft of the engine. In the latter type, the start¬ 
ing switch is mounted on the gear housing, which is integral with 



Fig. 298. North East Dynamotor with Silent-Chain Drive. Starting 

Switch Shown at Right 

Courtesy of North East Electric Company, Rochester, New York 


the bedplate of the dynamotor. In this case the drive as a gener¬ 
ator is IJ times engine speed, while as a starting motor the 
reduction through the gear is approximately 40 : 1. 

Regulation. The regulation is by means of a differential wind¬ 
ing or bucking coil, in connection with an external resistance auto¬ 
matically cut into the shunt-field circuit by a relay in series with the 
battery cut-out. See “limiting relay”, Fig. 299. The “master 
relay” is the battery cut-out, and the condenser is to reduce sparking 
at the contacts of these relays. 

Protective Devices. There is a fuse in the field circuit of the 
generator, but fuses are not employed on the lighting circuits. 

* The voltage of any system may be determined by counting the number of cells in the 
storage battery, and multiplying by 2 in the case of a lead battery, or multiplying by where 
an Edison battery is used. 






^srn\miNG svyncH. 




FtE3ISTF\NC£:. UniTlNG 

ncLPo^. 


nf\ST£R RE3ISrf\NCE 

REUf^r. 


Fig. 299. Diagrammatic Section of North East Dynamotor, Showing Regulator (Limiting 

Relay) and Cut-Out (Master Relay) 
















































































Heajllight Ground 


454 


ELECTRICAL EQUIPMENT 




Wiring Diagrams. A graphic diagram of the North East 


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cfl ^ 

MO? 


5 2 
t: 

i c 

5 0/ 

M O 


c/: w cu 


installation on the Dodge is shown in Fig. 300. This is a 6-cell or 
12-volt system single-wire type. The sprocket on the forward end 


Fig. 300. Diagrammatic Layout of North East Installation on Dodge Cars 
Courtesy of North East Electric Company, Rochester, New York 







































oj 
'Vi 

(a 

4 > P 

-P -ri 
4 -> 

h P 
0) n) 


o 

is; 

l-H 

K 

O 


m 


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E-i 


w 


Fig. 301. Diagrammatic Layout of North East 12-Volt Installation on Krit 1915 Automobiles (14-Volt Lamps) 










































45G 


ELECTRICAL EQUIPMENT 


of the machine drives from a similar but much larger sprocket on 
the forward end of the crankshaft of the engine through a silent 
chain. The wiring diagram of the Krit 1915, Fig. 301, will be 

recognized as being the 
same as the Dodge, except 
for the use of two wires 
throughout. Fig. 302 
shows the wiring diagram 
of an 8-cell or 16-volt 
system, but the battery is 
divided for the lighting 
circuits so that —9-volt 
lamps are used, whereas 
14-volt bulbs are necessary 
on the Dodge installation 
as the entire battery is 
used in series for lighting. 
The wiring of the 12-cell 
or 24-volt system is shown 
in Fig. 303. In this case 
the battery is divided for 
lighting so that 7-volt 
lamps are employed. Such 
a system is usually desig¬ 
nated as 24—6-volt, while 
the previous one would be 
a 16—8-volt. The North 
East installation for Ford 
cars is 24—14-volt. With 
the exception of the Dodge, 
the two-wire system is 
employed on the instal¬ 
lations mentioned. 

Instructions. The 
indicator shows when the 
battery is charging or dis¬ 
charging and accordingly 
should indicate OFF when 



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Fit 


302. Wiring Diagram for 16-V'olt North East 
System Using 834—9-Volt Lamps 






















































































































457 


ELECTRICAL EQUIPMENT 



3 

io 

p> 

n 

oD 

■dW 

in 

,5 


Fig. 303. Wiring Diagram for 24-Volt North East System Using 7-Volt Lamps 






































































































458 


ELECTRICAL EQUIPMENT 


the engine is idle and no lamps are lighted. A discharge reading under 
such conditions would indicate the presence of a ground, short-circuit, 
or failure of the battery cut-out to release. Should the generator fail 
to charge the battery, note whether the field fuse has been blown by 
short-circuiting the fuse clips with the pliers or a piece of wire while 
the engine is running at a moderate speed. Look for cause of failure 
before replacing the fuse. If the fuse has not blown, see whether 
battery cut-out is operating; look for loose connections at generator, 
cut-out, and battery. If the battery is properly charged, loose con¬ 
nections are also most likely to be the cause of failure of the starting 
motor; or, any of the instructions covering brushes, commutator, etc., 
as given previously, may apply. 

Battery Cut-Out and Regulator {Relays). In every case where it is 
necessary to make repairs on starter-generators equipped with the 
earlier type cut-out and regulator (relays), 1283 (12-volt), 1860 
(16-volt), 2501 (24-volt), 1900 (16-volt), and 2503 (12 and 24-volt), 
it is advisable to replace the cut-out entirely, installing a later and 
improved type, 1196 (12-volt), or 1197 (24-volt and 16-volt). In 
order to adapt the starter-generator to the 1196 and 1197 cut-out, or 
relay units, it is necessary to cut out the bosses on the commutator 
end bearing in which the studs holding the original relay were 
screwed. This will provide the clearance required to prevent ground¬ 
ing of the nuts which secure the units to their baseboard. As a 
further precaution against grounding, it will be necessary to cut away 
that portion of the gasket retainer which would be liable to come 
into contact with the armature of the master relay. 

Fasten down the baseboard which carries the relays by screwing 
the resistance unit studs into the holes which were used for the former 
resistance studs. Before making connections on the relay, draw 
tight all leads which come from inside the starter-generator so as to 
take up whatever slack they have; then tie them together with string 
to prevent their slipping back. No loose wire must be left inside the 
starter-generator, because of its tendency to be drawn in between the 
armature and the pole pieces. The connections on the four-terminal 
type starter-generator are made as follows: 

Looking at the starter-generator from the driving sprocket end, 
the main terminals 1, 2, 4, and 3 of the starter-generator are consid¬ 
ered as being numbered in anti-clockwise rotation. Fig. 304. Viewing 


ELECTRICAL EQUIPMENT 


459 


the relay unit as mounted on the starter-generator with the larger, or 
master relay, at the left, the four binding posts a, b, c, and d are 
designated from left to right in the same illustration. To relay bind¬ 
ing post a, connect lead (red) coming from starter-generator terminal 
2. To relay binding post b, 
connect lead (black) coming 
direct from starter-generator 
terminal 3. To relay binding 
post c, connect lead (green) 
from starter-generator ter¬ 
minal 4. To relay binding 
post d, connect lead (yellow) 
from starter-generator shunt- 
field coils. It is always advis¬ 
able to check the identity of the 
leads by inspection and test. 

In order to make a posi¬ 
tive distinction between the d 
lead and the 5 lead, both of 
which are in electrical connec¬ 
tion with the starter-generator 
terminal 3, the following test 
should be made: Using the 
test-lamp outfit, send current 
from starter-generator ter¬ 
minal 3, through each of these 
wires in turn, and note appear¬ 
ance of the lamp. When the 
direct lead (6 lead) is in circuit, 
the lamp will burn with full 
brilliance, but when the d lead, 
which includes the starter-generator shunt-field coils, is in circuit, the 
lamp will be noticeably dimmer. 

Five-Terminal Type Unit. The connections on the five-terminal 
type generator-starter unit are made as follows: Looking at the 
starter-generator. Fig. 305, from the driving sprocket end, the main 
terminals 1, 5, 2, 4, and 3, respectively, of the unit are numbered in 
anti-clockwise rotation (to the left). Viewing the relay unit as 



.S^r/rj?TER-(7£N£:R/JTOR 





Fig. 304. 


Internal Wiring Diagram for North East 
Model "B” Starter-Generator 























































4G0 


ELECTRICAL EQUIPMENT 


mounted on the starter-generator with the master relay at the left, 
the four binding posts a, b, c, and d are designated from left to right 
as shown in the illustration. Proceed with the instructions as given 
for the four-terminal type starter-generator as given. The new type 
relays 1196 and 1197 are regularly furnished with local connec¬ 
tions, as shown in Fig. 304, 
but it will be necessary to 
. make the following altera-^ 
tions when applied to the 
five-terminal type starter- 
generator, so that the relay 
connections will conform to 
the diagram in Fig. 305. 
Remove the jumper lead that 
connects the frame of the 
master relay to the rear con¬ 
tact terminal on the limiting 
relay; remove from relay 
binding post a the left-hand 
resistance-unit lead. 
Lengthen this lead by splic¬ 
ing a piece of the same kind 
of wire to it, and solder it to 
the limiting relay contact ter¬ 
minal, from which the jumper 
has been removed. To this 
terminal must also be sol¬ 
dered the lead coming from 
starter-generator terminal 5. 
(In some starter-generators 
this lead includes the field 
fuse.) 

The condenser in the early models is mounted between the field 
coils. One condenser lead must either be connected to the relay 
binding post a as shown in either Fig. 304 or Fig. 305 or be spliced 
to the wire leading to it. The other condenser lead must either be 
connected to the relay binding post d or spliced to the shunt-field 
wire leading to it. 




Fig. 305. Internal Wiring Diagram for Model “D” 
and Model “F” Starter-Generators 

































































Fig. 306. \'iew of Essential Parts of North East Starting Switch 
Courtesy of North East Electric Company, Rochester, New York 












462 


ELECTRICAL EQUIPMENT 


Starting Sicitch. When its operation indicates that the con¬ 
tactor blades have worn, the starting switch should be dismounted, 
and, if necessary, new blades should be inserted. To disassemble the 
switch, proceed as follows: (1) Remove the spring 2265, Fig. 306, on 
the switch case 2365; (2) remove the cotter pin from the collar 2416; 
(3) withdraw the shaft and lever 2401, together with the spring 
1818; (4) remove the three screws which hold the cover 2404 in place, 

and remove the cover; 
(5) remove the stop 2457; 
and (6) disconnect the 
spring 1813 from the arm 
of the ratchet and re¬ 
move the contactor mem¬ 
ber 2344. 

If, upon inspection, 
the contacts are found to 
be in such a condition 
that their renewal is nec¬ 
essary, make a replace¬ 
ment of the entire cover 
member 2404 and the 
entire contactor 2344. 
Before placing these new 
parts in the switch, the 
following points should 
receive careful attention: 
the front edges of the contact blocks should be slightly rounded so 
as to eliminate the possibility of these edges catching on each other 
when the switch is being operated. The supports on the cover 
must be adjusted so that they lie parallel with the faces of the 
contact blocks. 

The upper surfaces of the supports must be .010 to .015 inch 

4 

lower than the contact surface of the block. Care should be taken 
that the upper surface of the contact blocks are ^ inch above the 
inner surface of the cover. A small steel straightedge laid upon 
tlie face of the contact block and extended over the supports, 
as shown in Fig. 307 (a), will serve as a means of checking these 
dimensions. 



rcj 

Fig. 307. Assembly of Starting Switch 
Courtesy of North East Electric Company, Rochester, New York 
























ELECTRICAL EQUIPMENT 


4()3 

Before placing in service, the contact surfaces must be carefully 
cleaned and lubricated with a very small quantity of vaseline. To 
reassemble the switch: (1) Connect the spring 1813, Fig. 306, to the 
arm of the ratchet; (2) place the contactor member 2344 in 
the switch case in such a position that the ratchet will lie against the 
pawl 1830; and (3) hold the switch case in the left hand, lever side up, 
and insert the right forefinger through the hole in the switch case 
and introduce the pawl into the first notch of the ratchet. Fig. 307 (b ); 

(4) hold these parts carefully in position and replace the cover 2404, 
Fig. 306, fastening it to the switch case by means of the three screws; 

(5) insert the stop through the hole in the switch case and replace it 
upon the ratchet plate in such a position that the elongated portion 
of the stop will lie between the raised projection which is found on 
the ratchet plate and the end of the short lever on the pawl as showm in 
Fig. 307 (c). It is very important that the stop be placed in the 
switch right side up. Fig. 307 (d) illustrating the proper method of 
doing this. (6) Place the spring on the shaft and replace the shaft in 
the switch, taking care while entering the shaft not to disturb the 
arrangement of any of the switch parts; (7) replace the collar and the 
cotter pin; and (8) connect the spring 2265 with the lug on the switch 
case. ' A drop of light oil should be applied to the bearing point at each 
end of the switch shaft 2401. 

Switch Tests. To determine wFether the switch has been 
assembled correctly, pull the lever through the full length of its stroke 
and allow it to return slowly to its initial position. If the switch 
is properly assembled, three distinct clicks will be heard while the lever 
is being moved through its stroke, and a snap will occur just before 
the lever comes back to its initial position. The switch should be 
tested electrically, as follows: 

Ground Test. Using the lamp-test set as shown in" Fig. 263 
and following Part V, hold one contact point on the switch case and 
then connect the other to the two contact studs. The test lamp will 
not light unless there is a ground. 

Operation Test. Hold one of the test points in contact wdth each 
of the two studs, and turn the lever through its stroke. If the switch 
is in proper working condition, the test lamp will light up just after 
the first click of the switch and continue to burn until the final 


snap occurs. 


Gray & Davis Test Outfit 


4(i4 


ELECTRICAL EQUIPMENT 


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TABLE V—(Continued) 
Gray & Davis Test Outfit 


ELECTRICAL EQUIPMENT 


465 




































































460 


ELECTRICAL EQUIPMENT 


Replacing Dodge Chain. When the driving chain on any equip¬ 
ment operated in this manner has worn to a point where it no longer 
makes proper contact with th^ sprockets (the chain being adjusted to 
the correct tension), it will be necessary to replace it. While the 
following instructions for ‘‘fishing” the chain through the housing 
apply particularly to the Dodge car, with little modifications 
here and there they will be found equally applicable to all similar 
installations. 

Having removed the old chain, pass a short piece of wire through 
the end of the new chain. Fig. 308. Then start the chain on the 
lower side of the sprocket, as shown in the illustration, hooking the 
wire through the sprocket to keep the chain in mesh, and slowly turn 
the engine over by hand until the chain appears at the top of the 
sprocket. Then remove the wire from the sprocket, hold the end of 
the chain, and continue to turn the engine over until the chain is in 

a position to apply the 
master link. 

Mechanical and Elec¬ 
trical Characteristics. 
When it is desired to 
make bench tests of any 
of the North East appa¬ 
ratus with the aid of the 
outfit described in connec¬ 
tion with the Gray & 
Davis tests, the data 
shown in Table V will 
be found valuable for 

left-hand columns give 
the mechanical charac¬ 
teristics, with the aid of 
which the unit mav be 

t/ 

identified, while the right-hand columns give the electrical character¬ 
istics, such as the charging rate, torque in foot-pounds with given 
current input, cutting-in and cutting-out points of the master relay 
(battery cut-out), air gaps for the limitation relay, and the resistance 
of the units. 


checking purposes. The 



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Fig. 308.—Diagram Showing Method of Inserting 
Chain in North East Equipment on Dodge Cars 

















ELECTRICAL EQUIPMENT 


467 


REMY SYSTEM 

Six=Yolt; Two=Unit; Single=Wire 

Generator. Of the multipolar (four-pole) shunt-wound type 
' of generator combined with ignition timer and distributor and 
designed to be driven at IJ times crankshaft speed, several models 
are made, of which one is shown in Fig. 309. In this case, both the 
regulator for the generator and the battery cut-out are mounted 
directly on the generator. On some of the models only the regu¬ 
lator is so mounted, the cut-out being placed on the dash of the car, 
while on others no 
independent regu¬ 
lating device is 
required as the 
third-brush type 
of regulation is 
employed (on bi¬ 
polar generator). 

Regulation. 

In accordance 
with the model of 
generator and the 
requirements of 
the engine to 
which it is to be fitted, either the constant-voltage method of 
regulation using a vibrating regulator mounted on the generator 
or the third-brush method is employed. 

Constant-Voltage Method. The regulator for the generator is 
similar in principle to that described in connection with the Bijur 
system. It consists of an electromagnet; two sets of contact points, 
two of which are mounted on springs; a pivoted armature which may 
move to make or break the circuit; and a resistance unit. When 
running at too slow a speed to produce its maximum output, the 
generator field is supplied with current passing directly through the 
regulator contact points, which are held together by a spring. As 
soon, however, as the speed of the generator increases to a point 
where it tends to cause its output to exceed the predetermined 
maximum, the charging current which is flowing through the coil 
of the electromagnet energizes it so such an extent as to cause it to 



Fig. 309. Remy Ignition Generator and Distributor 
Courtesy of Remy Electric Company, Anderson, Indiana 




468 


ELECTRICAL EQUIPMENT 


pull the armature down. This separates the contacts and causes 
the field current to pass through the resistance unit, thus decreasing 
the field current and, in turning, decreasing the generator output, 
which reduces the exciting effect on the electromagnet and causes 
it to release its armature, cutting the resistance out of the field cir¬ 
cuit. The latter immediately builds up again, and the operation is 
repeated as long as the speed remains excessive for the generator, 
which is thus supplied with a pulsating current to excite its fields, 
and its output is held at a practically constant value. 

Third-Brush Method. The third-brush method of regulation is 
based upon the distortion of the magnetic field of a generator at 
high speeds. When running at low speeds, the magnetic flux of a 
generator is evenly distributed along the faces of its field pole pieces, 
but at‘high speeds there is a tendency to drag it out of line in the 
direction of the rotation of the armature. It is then said to be 
distorted. The third brush, which supplies the exciting current to 
the field winding, is so located with relation to the main-line brush 
of opposite polarity that this distortion of the magnetic flux reduces 
the current which it supplies to the fields. This decrease in the 
exciting current of the field causes a corresponding decrease in 
the output of the generator, and as the distortion of the magnetic flux 
is proportional to the increase in speed, the generator output falls 
ofl‘ rapidly the faster it is driven above a certain point, so that it is 
not damaged when the automobile engine is raced. 

Thermostatic Switch. More of the current produced by the 
generator is used for lighting purposes in winter than in summer, in 
the proportion that the demands for house lighting vary with the 
change of the seasons. Added to the decreased efficiency of the stor¬ 
age battery in cold weather, this tends to place a greatly increased 
load on the generator in the winter months. If the generator, as 
installed, were regulated to produce sufficient current to take care of 
this maximum demand, it would keep the storage battery in a con¬ 
stant state of overcharge in summer and would be likely to ruin the 
plates through excessive gassing. The Remy engineers have accord¬ 
ingly developed a method of regulation that will automatically com¬ 
pensate for the difference in the demand with the changing seasons, 
consisting of a thermostatic switch in connection with the third-brush 
control; it will be found, among others, on the Reo 1917 models. 


ELECTlllCAL EQUIPMENT 


469 


To gain a clear idea of the action of an electric thermostat, the 
heating effect of the current mnsf be kept in mind; also that different 
metals have different coefficients of expansion, i.e., some will expand 
more than others under the influence of the same degree of heat. 
Electric thermostats have been 
in use for years as automatic 
fire alarms and as temperature¬ 
controlling devices in incubators 
and for residence heating, and 
within the past few years they 
have come into use on the auto¬ 
mobile to control the circulation 
of the cooling water and the 
suction of the engine in accord¬ 
ance with variations in the tem¬ 
perature. The device consists 
of a thermal member, or blade, of 
two different metals riveted together at their ends. This member is 
held fast at one end and at the other it carries a contact point, 
designed to complete the circuit by touching a stationary contact. 
Under the influence of an increase in temperature, one of the metals 




Fig. 310. 


Details of Remy Thermostatic 
Switch 



expands more than the other and thus springs this member, or blade, 
away from the stationary contact. 

The details of the Remy thermostat are shown in Fig. 310. B is 
the thermo-member carrying the silver contact C, and is supported on 





























































470 


ELECTRICAL EQUIPMENT 


a strip of steel A. A also carries the resistance unit E, which is a 
short coil of high-resistance wire wound on heavy mica insulation. 
.1 and B are riveted together at the end D so as to insulate them from 
each other. The two metals composing B are spring brass and nickel 
steel, the strip of spring brass being placed on the lower side of 
the blade. Sufficient tension is placed on this strip, by means of the 
adjusting nut F, to keep the points firmly in contact at temperatures 
below 150° F. This adjustment is made by the manufacturer and is 
permanent. 

As shown in the wiring diagram. Fig. 311, which illustrates the 
relation of the thermo-switch to the third-brush method of regulation, 
it will be noticed that the switch is placed near the commutator of the 
generator, as that is the hottest part of the machine when it is in 



r 





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E 


T/f^/^M03TJ3T CLOSED 



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Fig. 312. Photographic Reproductions and Diagrams of Action of Thermostatic Switch 

When Closed and Opened 

Courtesy of Remy Electric Company, Anderson, Indiana 


operation. It will be noticed also that when the contact points of the 
thermo-switch are open, as shown in the illustration, the current 
supplied to the field by the third brush must pass through the resist¬ 
ance unit of the switch, thus cutting it down. This is the position 
for warm-weather running, when not so much of the current is required 
for lighting, and when the storage battery is at its best. When the 
temperature of the air about the thermo-switch exceeds 150° F., the 
movable blade is warped upward, owing to the greater coefficient of 
expansion of the brass as compared with that of the nickel steel. The 
contact points will accordingly remain open as long as the temperature 
exceeds this degree. When it falls below that point, the quicker 
contraction of the brass pulls the blade down, and the points again 
make contact, cutting out the resistance and increasing the output 













ELECTRICAL EQUIPMENT 


471 


of the generator, diagrams of the thermo-switch in its closed and open 
positions being shown at the right, and a halftone of the switch at the 
left in Fig. 312, while the curves. Fig. 313, show the increase in the 
current output brought about by the closing of the thermo-switch 
points. The path taken by the current when the points are open and 
when they are closed is 
indicated by the dotted 
lines in the diagrams. Fig. 

312. The curves show 
that with the thermo¬ 
switch open, the maxi¬ 
mum current output of 
the generator is limited 
to 14 to 15 amperes, 
while with the switch 
closed it rises to 20 to 
22 amperes. The switch will normally remain closed after the engine 
has been idle for any length of time; but in summer it will open after 
driving a few miles, while in winter it will probably remain closed, 
no matter how much the car is driven. 

Starting Motor. The motor is the 6-volt 4-pole series-wound 
type, illustrated in Fig. 314, mounted either with gear reduction 





Fig. 314. Remy Starting Motor with Outboard Type Bendix Pinion 


and over-running clutch, or with automatically engaging pinion for 
direct engagement with flywheel gear, as described in connection 
with the Auto-Lite. The latter is known as the Bendix gear. The 
control is by independent switch. 

Instruments and Protective Devices. An indicator, or telltale, 
shows when the battery is charging or discharging, and also serves 







472 


ELECTRICAL EQUIPMENT 


to indicate any discharge, in all except the starting-motor circuit, 
due to grounds or short-circuits. All lamp circuits are fused, and a 
fuse is inserted in the regulator circuit. 

Remy Single=Unit 

A Mechanical Combination. While termed a single-unit type, 
this is actually two independent units combined, mechanically and not 
electrically, so that it bears no resemblance to the single unit on which 
both field and armature windings are carried on the same pole pieces 
and armature core. The field frame for the two units is a single 

casting, Fig. 315, but the 
magnetic circuits of both 
the generator and the motor 
are entirely independent, and 
each is a separate unit. They 
are combined in this manner 
solely for convenience in 
mounting where space is 
limited. The vibrating type 
of voltage regulator is em¬ 
ployed in connection with 
the generator, while the start¬ 
ing motor operates through 
a train of reducing gears 
and an over-running clutch. 
Apart from the combination 
of the two units and the 
method of starting drive 
which this entails, the sys¬ 
tem is the same in its essentials as where the units are mounted 
independently. 

Wiring Diagrams. Velie. Fig. 31G shows the installation on 
\"elie. Model 22, and the details will be plain with further explanation. 
The ‘'ratchet reversing switch”, shown in the diagram, is for 
controlling the ignition current, and it is designed to reverse the 
direction of this current each time the switch is turned on in order to 
prevent the formation of a crater and cone on the ignition interrupter 
contacts, as previously described, thus keeping the points in good work- 



Fig. 315. Combined Field Frame of Generator 
and Motor for Remy Single-Unit System 













ELECTRICAL EQUIPMENT 


473 



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474 


ELECTRICAL EQUIPMENT 


iiig order for a much longer period. The dash and tail lights are 3^- 
volt lamps, wired in series, so that the failure of one puts the other out, 
thus giving an indication at the dash of the failure of the tail light. 

Oakland. The Remy installation on Oakland Model 32 is 
shown in Fig. 317. The chief distinction between this and the pre¬ 
vious diagram is the employment of a single 10-ampere fuse on the 
lighting circuits instead of independent fuses on each circuit. 
“Breaker box” refers to the ignition-circuit contact-breaker, or 
interrupter, as it is variously termed. The starting motor in this 
case is fitted with the Bendix drive. 

Reo. On the Reo installation. Fig. 318, the starting motor is 
mounted on the transmission housing and drives to a shaft of the 
latter through a worm gear. In this case the starting switch is 
mounted directly on the starting motor, and an ammeter is supplied 
on the charging circuit instead of a telltale, or indicator. 

National. A typical installation of the single unit, or so-called 
double-deck unit, is shown in Fig. 319. This is on the National 
six-cvlinder model and is a two-wire system. It is not intercon- 
nected with the ignition system, so there are no ground connections, 
and no fuses are employed. 

Instructions. These instructions cover the systems which 
include the ignition. For instructions applying to the double-wire 
system on cars having an entirely independent ignition system, like 
the National, see instructions under Auto-Lite, Delco, Gray & 
Davis, and others, for failure of generator or motor, short-circuits, 
and the like. 

Battery Discharge. In systems of this type, discharge of the 
battery may be due to failure to open the ignition switch after 
stopping the car. The amount of current consumed is small but 
in time it will run the battery down. The indicator or the ammeter, 
according to which is fitted, will show a discharge. An entire fail¬ 
ure of the current may indicate: a loose connection at battery ter¬ 
minals, at battery side of starting switch in connection with a blown 
main fuse (Oakland), or a loose battery ground connection; a loose 
connection at motor side of starting switch or at starting motor, 
or a broken wire between the switches. (See previous instructions 
on other makes for testing with lamp set for broken or grounded 
circuits.) 


ELECTRICAL EQUIPMENT 


475 



Fig. 317. Wiring Diagram for Remy Installation on the Oakland, Model 32 













































































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1 


Fig. 319. Wiring Diagram for Remy Double-Deck Unit on the National Six 












































































































































478 


ELECTRICAL EQUIPMENT 

Failure of Lightinq, Ignition, Starting. When the lights and 
ignition fail but the starting motor operates, it indicates a short 
or open circuit between the starting switch and the main fuse (Oak¬ 
land). This fuse should first be examined and, if blown, a search 
should be made for the ground or short-circuit causing it, before 
putting in a new fuse. The fault will be in the wiring Letween the 
switch, lights, and ignition distributor. See that all connections, 
including those on fuse block, are tight. When the lights fail but 
the ignition and starting motor operate, the trouble will be found 
either in the circuits between the lighting switch and lamps; in the 
lamps themselves, as a burned-out bulb causes a short-circuit; or 
from loose connections in these circuits. Failure of the ignition, 
with the remainder of the system operating, may be traced to loose 
connections at the ignition switch, coil, or distributor; poor ground¬ 
ing of the ignition switch on the speedometer support screw; or to 
open or short-circuits between the ignition switch and the distributor. 
Further detail instructions on ignition are given in Ignition, Part 11. 

Dim Lights. When all the lights burn dimly, the most prob¬ 
able cause is the battery, but if a test shows this to be properly 
charged, a ground between the battery and the starting switch or 
between the latter and the generator may be responsible for leakage. 
Other causes are the use of higher candle-power lamps than those 
specified, the use of low efficiency carbon-filament bulbs, or failure 
of the generator to charge properly. 

Examine generator-field fuse and if blown, look for short- 
circuits before replacing, as previously instructed. A simple test of 
the generator may be made by switching on all the lights with the 
engine standing. Start the engine and run at a speed equivalent 
to 15 miles per hour or over. If the lights then brighten percepti¬ 
bly, the generator is operating properly. This test must be made 
in the garage or preferably at night, as the difference would not be 
sufficiently noticeable in daylight. 

If the generator fuse is intact, examine the regulator relay con¬ 
tacts. If the points are stuck together, open by releasing the relay 
blade with the finger. Clean and true up points as previously 
instructed and clean out all dust or dirt from relay before replacing 
cover. Particles of dirt lodged between the points will prevent 
the generator from charging properlv. 


ELECTRICAL EQUIPMENT 


479 


The failure, flickering, or dim burning of any single lamp will 
be due to a burned-out bulb, to loose or fraycnl connections at lamp 
or switch, to a bulb loose in its socket, or to an intermittent ground 
or short-circuit in the wiring of that particular lamp, or to the frame 
of the lamp nor being grounded properly. Where dash and tail 
lamps are in series, examine both bulbs and replace the one that 
has burned out. Test with two dry cells connected in series. 

Ammeter. When the indicator, or ammeter, does not register a 
charge with the engine running with all the lights out, stop the engine 
and switch on the lights. If the instrument gives no discharge 
reading, it is faulty. If it shows a discharge, the trouble is in the 
generator or connections. In case the ammeter registers a discharge 
with all the lights ofl‘, ignition switch open, and engine idle, examine 
relay contacts to see if thev remain closed. If not, disconnect the 
batterv. This should cause the ammeter hand to return to zero: if 
it does not, the instrument is out of adjustment. With the ammeter> 
or indicator, working properly, and the relay contacts in good con¬ 
dition, a discharge then indicates a ground or short-circuit. When 
examining the relay for trouble, do not change the adjustment of 
the relay blade. 


SIMMS=HUFF SYSTEM 
Twelve=Volt; Single=Unit; Single=Wire 

Dynamotor. The dynamotor is of the multipolar type having 
six poles, as illustrated in Fig. 320, which shows the field frame, coils, 
and poles. Fig. 322 illustrates the assembled brush rigging, while 
Fig. 321 shows the complete unit with the commutator housing plates 
removed. 

Regulation. Regulation is by reversed series field, in connection 
with a combination cut-out and regulator. The regulator is of the 
constant-potential type and is combined with the battery cut-out. 
It is connected in circuit with the shunt field of the generator, and the 
vibrating contacts of the regulator cut extra resistance into this circuit 
when the speed exceeds the normal generating rate. There is also 
a differential compound winding of the fields, the two halves of which 
oppose each other at high speeds. 

Instruments. An ammeter is supplied, showing charge and 

discharge. 


480 


ELECTRICAL EQUIPMENT 


Dynamotor Connections. The clyiiamotor has two connections, 
one at the bottom of the forward end plate, marked DYXH-, and 
the other on top of the field yoke designated as FILED. As The 
system is a single-wire type, the opposite sides of both circuits are 
grounded within the machine itself. The terminals on the cut¬ 
out are marked BAT+, DYN-f, and DYX —, BAT — , and ELI). 




Fig. 320. Field Frame, Poles, and Windings 
for Simms-Huff Dynamotor 


Fig. 321. Brush Rigging for 
Simms-Huff Dynamotor 



Fig. 322. Simms-Huff Dynamotor with Commutator Housing 

Plates Removed 

Courtesy of Simms Magneto Company, East Orange, New Jersey 


BAT-I- connects through a 12-gage wire to the negative side of the 
ammeter and thence to a terminal on the starting switch. This con¬ 
nects it permanently to d-R of the battery through the ammeter. 
This wire supplies the current to the distributing panel, from which 















ELECTRICAL EQUIPMENT 481 

current is supplied to the lamps and horn. DYN -f~ connects through 
a similar wire to the plus terminal of the dynamo, while DYN— and 



-<- -♦ 



Fig. 323. Wiring Diagram for Simms-Huff Starting and Lighting Systems 

BAT— connect with the — L terminal of the storage battery through 
a wire of the same size. 

Change of Voltage. The system is known as 6—12-volt type, 
signifying that the current is generated at 6 volts, but is employed for 









































































































482 


ELECTRICAL EQUIPMENT 


starting at 12 volts. There are accordingly 6 cells in the storap 
battery, and the latter is charged by placing the two halves of it, 
consisting of two 3-cell units, in parallel. This is indicated in the 

R/C^/YT /YE/ID L/7/^rP 



LEFT HEPD L/7F7P 


Fig. 324a. Complete Wiring Diagram for 1916-17 Maxwell Cars (see Fig. 324b) 

Courtesy of Simms Magneto Company, East Orange, New Jersey 

upper diagram, Fig. 323, also in the middle diagram, which shows the 
connections for charging. In the lower diagram of the figure are 
shown the starting connections, the switch being connected to throw 
the 6 cells of the battery in series, so that the unit receives current at 


































































































ELECTRICAL EQUIPMENT 483* 

12 volts for starting, thus doubling its power. Six-volt lamps are 
employed and are supplied witli current from the left-hand section of 
the battery, marked 1, as shown in the upper part of the diagram. 



Fig. 324b. Complete Wiring Diagram for 1916-17 Maxwell Cars, Showing Details of Dash 

Panel and Batteries 

Courtesy of Simms Magneto Company, East Orange, New Jersey 


Starting Switch. This is mounted on the left side of the gear¬ 
box housing (iMaxwell) and is so arranged as to connect the entire 
battery in series for starting, thus giving current at 12 volts for this 
purpose. The same movement of the starting switch also puts the 























































































































































484 


ELECTRICAL EQUIPMENT 


battery in circuit with the ignition system so that, as soon as the 
engine starts and the switch is released, it automatically disconnects 
the battery from the ignition, and the engine then runs on the magneto 
(dual ignition system). 

Wiring Diagram. Fig. 324a and Fig. 3246 show the wiring 
diagram complete of the ignition, starting, and lighting systems as 
installed on the 1916 and 1917 Maxwell cars. The heavy lines indicate 
the starting-system connections, while the light lines are the wires 
leading from the generator to the battery (through the regulator and 
cut-out), and the various connections for the ignition and the lamps. 
They show very plainly, upon tracing them out, the relation of the 
regulator and cut-out to the generator and the battery, as well as the 
method of dividing the six cells of the battery into two units for light¬ 
ing service, and the coupling of all the cells in series for starting. It 
will be noted also that the storage battery is not utilized for ignition, 
as the starting switch closes the,circuit of a dry battery of four cells 
for ignition when starting the engine. As the starting switch auto¬ 
matically opens this circuit when released, there is no danger of this 
battery being inadvertently left in circuit. 

At the upper left-hand corner of the diagram, complete details of 
the ignition circuit and of the magneto itself are shown. The 
magneto (Simms) is of the true high-tension type, having primary 
and secondary windings on the armature core, as well as a condenser 
incorporated in it. As this sketch shows not only the relation of high- 
tension type of magneto to the plugs but also that of the essential 
parts of the magneto, as well as the relation of the ignition system to 
the starting and lighting systems through the combination starting 
and ignition switch, it will repay close study. The number of wires 
makes it appear as if this were a two-wire system, but upon noting 
the ground connections at the various terminals it will be evident 
that it is not. 

Instructions. The Simms-Huff system as above described is 
standard equipment on the Alaxwell cars. The combination cut¬ 
out and regulator is mounted on the rear of the dash panel carrying 
the ammeter and switch. It consists of two distinct devices, the 
cut-out serving the usual purpose of protecting the battery when 
the generator voltage drops, and the regulator limiting the current 
output of the dynamo as the engine speed increases. In connection 


ELECTRICAL EQUIPMENT 


485 


with it a special regulator switch is provided. This is located on 
the right side of the dash panel and has two positions, HIGLI 
and LOW, the latter inserting additional resistance in the field 
circuit of the dynamo to further limit its output when the car is 
driven steadily at high speed on long runs. This switch is kept in 
the PUGH position for all ordinary driving and only shifted to 
LOW as above mentioned. 

Failure of Cvt-Out or of Regulator. Should the ammeter pointer 
go to the limit of its travel on the discharge side, this indicates that 
the cut-out contact points have failed to release on the slowing 
down of the generator. The latter also will continue to run as a 
motor after the engine is stopped. Llisconnect the two wires from 
the terminals on the generator and wrap them with friction tape 
to prevent their coming in contact with any metal parts of the car. 
Clean and true up contact points as outlined in previous instruc¬ 
tions. An unusually high reading on the charge side of the ammeter 
will indicate a failure of the regulator to work. If an inspection 
shows no sign of broken or crossed wires, loose connections, or other 
obvious trouble, the manufacturers recommend that the unit be sent 
to them. In the case of the owner, it is recommended that no 
attempt be made to correct faults in the cut-out or in the regulator, 
but that it be referred to the maker of the device or to the nearest 


service station. 

Generator Tests. To determine whether a short-circuit or a 
ground exists in the brush holder, pull up all the brushes and with the 
aid of the lamp-test set, test by applying one end to the frame and 
the other to the main terminal post. The lamp will light if there is a 
short-circuit or a ground between the brush holder and the frame. 
A similar test may be made for the armature by pulling up all the 
brushes (or heavy paper may be inserted between them and the com¬ 
mutator) and placing one point on the commutator and the other on 
the shaft. The lighting of the lamp will indicate that the armature is 
grounded. In all tests of this nature where the lamp does not light 
at the first contact, it should not be taken for granted at once that 
there is no fault. Touch various parts of both members on clean 
bright metal. See that the points of the test set are clean, that 
the lamp filament has not been broken, and that the lamp itself has 
not become unscrewed sufficiently to break the circuit between it and 


48G 


ELECTRICAL EQUIPMENT 


the socket. A good rule is always to test the lamp itself first; some¬ 
times the connecting plug of the set is not properly screwed into the 
socket. 

While the above test for the armature, if properly carried out, will 
show whether the latter is grounded or not, it will not give any indi¬ 
cation of an internal short-circuit in the armature itself. To deter¬ 
mine this, connect the shunt fields and run the unit idle as a motor, 
with the portable ammeter in the circuit, using the 30-ampere shunt. 
While running without any load the motor should not consume more 
than 7 amperes at 6 volts, i.e., using half the battery. Tests for 
grounds in the shunt field may be made with the lamp-test set, but to 
determine whether there is a short-circuit in the field, it is necessary 
to measure the resistance of its windings. If there is neither a short- 
circuit nor a ground in the field, the resistance of the windings should 
calculate approximately GJ ohms on units with serial numbers up to 
27,000, and approximately 4.8 ohms on starters above this serial 
number. 

The Simms-Huff is one of the very few, if not the only unit, that 
is belt-driven as a generator. Its normal output is 10 to 15 
amperes; so when the dash ammeter shows any falling oflf in this 
rate, with the engine running at the proper speed to give the 
maximum charging current, the belt drive of the generator should be 
inspected. If the ammeter reading falls off as the engine speed 
increases, it is a certain indication that the belt is slipping and that 
the generator itself is not being driven fast enough. Adjust the 
tension of the belt and test again. If this does not increase the output 
to normal, inspect the commutator and brushes, brush connections 
and springs, etc. See that the brushes have not worn down too far, 
and if necessary, sand-in. Failing improvement from any of these 
expedients, inspect the regulator. This should not be adjusted to give 
more current until every other possible cause has been eliminated; 
and before making any change in the adjustment of the contacts, see 
if cleaning and truing them up will not remedy the trouble. If 
necessary to adjust, do so very carefully, as increasing the current 
output by this means will also increase the voltage, and if the voltage 
exceeds the normal by any substantial percentage, all the lamps will 
be burned out at once. Trouble in the electrical unit itself will be 
most likely to appear in the brush holder. 


ELECTRICAL EQUIPMENT 


487 


M heiiever it is necessary to remove the front end plate over the 
commutator to inspect the commutator or the brushes, be sure that 
this plate w jnd hack the same way, and not accidentally turned round 
a sixth of a revolution, which would cause the motor to run backward. 
1 here is a slot in the front end of this plate to permit the brush holder 
to be moved backward or forward so as to give the best brush setting 
as a generator and as a motor. On most of the Simms-Huff units, a 
chisel mark will be found on each side of the fiber insulator under the 
main terminal post, indicating the factory brush setting. Checking 
this brush setting should be one of the further .tests undertaken before 
resorting to adjustment of the regulator. To do this, connect the 
j)ortable ammeter in the charging circuit (3()-ampere shunt) or, if 
one of these instruments is not available, the dash ammeter may be 
relied upon. 

Run the engine at a speed high enough for the maximum normal 
output; loosen the brush holder and move very slowly backward and 
forward, meanwhile noting the effect on the reading of the ammeter; 
and mark the point at which the best output is obtained. To test 
as a motor, connect the ammeter in circuit with half of the batterv 
and run idle. Move brush holder backward or forward to obtain best 
setting point, as shown by the ammeter reading, which, in this case, 
will be the minimum instead of the maximum. The unit should not 
draw more than 7 amperes when tested in this manner. If the best 
points for generating and running as a motor, as shown by these tests, 
are separated by any considerable distance, a compromise must be 
effected by placing the brush holder midway between them. If the 
dash ammeter does not appear to be correct, check it with the portable 
instrument or with another dash ammeter. 


SPLITDORF SYSTEM 
Twelve—Six=Volt; Single=Unit; Two=Wire 

Dynamotor. Both windings are connected to the same com¬ 
mutator on the dynamotor, which is of the bipolar type. 

Wiring Diagram. As the lamps are run on fi volts, the 6-cell 
battery is connected as two units of 3 cells each for lighting, and these 
units are connected in series-parallel for charging, as the dynamotor 
])roduces current at 6 volts. The remaining details of the connections 
will be clear in the wiring diagram, Fig. 325. 


488 


ELECTRICAL EQUIPMENT 


Six=Volt; Two=Unit 

Control. Switch. The starting switch is mounted on the 
starting motor. This switch automatically breaks the circuit as 
soon as the engine starts. The starting gear slides on spiral splines 
on the armature shaft, so that when the engine gear over-runs it, 
the starting gear is forced out of engagement. This gear is connected 



to a drive rod which also engages a switch rod, so that when the 
gear is forced out of mesh with the flywheel, it carries the switch 
rod with it and automatically opens the circuit. The switch contacts 
cannot stick, and no damage can result from holding down the switch 
^ pedal after the engine has started. 

Regulation. On the earlier models, a vibrating regulator was 
built in the generator, as illustrated in the section on Constant- 




























































ELECTRICAL EQUIPMENT 


489 


Potential Generators, but in later models an external regulator com¬ 
bined with the battery cut-out is employed. This is a constant 
voltage control of the vibrating type, similar to that described in detail 
in connection with the Bijur system, i.e., an electromagnet operating 
two spring-mounted armatures carrying contacts. 

Instructions. Should a discharge of 3 amperes or more be indi¬ 
cated on the ammeter when the engine is idle and all lights are off, 
this can be eliminated by slightly increasing the tension of the spring 
at the rear end of the cut-in armature. 



Splitdorf VR Regulator 
Courtesy of Splitdorf Electric Company, 
Newark, New Jersey 


Too great an increase in the tension of this spring will cause the 
cut-in, or charging point, to be raised too high, as indicated by 
the ammeter, which should 
be noted when making the 
adjustment. 

The voltage regulator 
as set at the factory is 
adjusted to limit the output 
of the generator to from 7 
to 10 amperes. Should it be 
necessary to increase this 
for winter running or for 
any other reason, it may 
be done by increasing the tension of the spring armature. The 
amount of movement of the adjusting screw at the rear end of the 
armature that is necessary will be indicated by the reading of 
the ammeter. The passage of current at the regulating contacts, 
which are in constant vibration while the engine is running above a 
certain speed, tends to roughen them. In time this may affect the 
charging rate and cause the points to stick together, which will be 
indicated by the ammeter showing a permanent increase in the charg¬ 
ing rate. If the latter becomes excessive, the cover of the regulator 
should be removed, and a thin dental file passed between the contacts 
on the stationary screw R, Fig. 326, and the movable contact on the 
regulating armature until both become smooth. In case it is neces¬ 
sary to remove the contact screw R for the purpose of smoothing its 
point, be sure to replace it at the same position, taking care that the 
ammeter reading does not exceed 7 to 10 amperes and that the lock¬ 
nut N is fastened securely. Lmder ordinary conditions, these con- 



490 


ELECTRICAL EQUIPMENT 


tacts should not require attention on an average oftener than once 
a year, but it would be well to examine them occasionally. 



By referring to Fig. 327, which is a diagram of the wiring of the 
generator and battery, the relation of these essentials to the regulator 
and cut-out are made clear. The field fuse shown on this diagram is 






























































ELECTRICAL EQUIPMENT 


491 


also indicated at F in Fig. 326. This fuse is a small piece of soft-alloy 
wire mounted between the post F and the contact-breaker. By 
referring to the wiring diagram, it will be noted that this fuse is in the 
shunt-field circuit, so that if it has been blown, the machine will not 
generate. It is designed to blow only at high speed with the battery 
ofi* the line and the vibrator contact R stuck. In actual practice, 
the regulator cut-out is mounted directly on the generator itself. 
The colors mentioned alongside the different wires are for purposes of 
identification so that' there will be no mistakes in making the 
various connections. 

Starting Motor. The starting motor is of the series-wound type 
and is similar in design to the generator. It is supplied with a Bendix 
drive as shown in Fig. 328. 

The starting motor has been designed so that when the oper¬ 
ator pushes a foot pedal or pulls a lever, a gear is carried into mesh 



Fig. 328. Splitdorf SU Starting Motor 
Courtesy of Splitdorf Electric. Company, Newark, New Jersey 

with a ring gear on the flywheel, and when the engagement is made, 
current is supplied to the motor. The gear is movably carried on the 
armature shaft by spiral splines. These splines tend to hold the gear 
in mesh while the engine is being cranked. As soon as the engine 
})icks up, it turns faster than the motor pinion which is operated with 
the fivwheel, and on account of the spiral splines the pinion is forced 
out of mesh with the gear on the flywheel. The gear, while being 
“drivingly” mounted on the armature shaft, is also mechanically 
connected to a connecting rod, which, as will be noted from the 
illustration, protrudes from the commutator end of the motor. 

The feature of this construction is, that no matter how long the 
operator may hold his foot on the starting pedal, the current is broken 
when the engine starts, as in the manner previously described. The 







492 


ELECTRICAL EQUIPMENT 


amount of current actually required for turning over the engine is 
thus controlled by the engine itself, and on account of the positive 
connection between one element of the switch and the starting 
gear, all possibility of the jaws of the starting switch sticking is 
eliminated. 

Instructions. Apart from the special adjustments of the starting 
switch, as mentioned in the deseription of its operation, the instrue- 
tions for maintenance are the same as those for other systems. In 
case this switeh does not operate properly, the sequence of operations 
as mentioned should be ehecked up, and the distances given verified. 
In case these distances have become greater through wear, they 
should be adjusted. To replace the brushes, remove the cover strap 
ov^er the commutator end of the unit, either generator or motor, 
put the two screws holding the rocker dise in place, disconneet the 
brush leads, and withdraw the brushes from the holders. It is 
important that the brushes slide freely in the holders and that the 
brush-lead terminals are clean and bright before replaeing the 
terminal screws. See that the springs rest fairly on the ends of the 
brushes and that their tension has not weakened. Follow instructions 
given in eonneetion with other systems for eare of the commutator. 

Failure of Engine to Start. When the starting motor cranks the 
engine after the starting pedal is depressed but fails to start the engine 
after a reasonable time, release the starting pedal and aseertain the 
cause, whieh may be due to the following: Ignition off, lack of fuel, 
fuel supply ehoked, cylinders needing priming due to weather con¬ 
ditions, or cylinders flooded from too much priming. 

Should the starting motor fail to erank the engine when the 
starting pedal is fully depressed, there is a possibility that the battery 
is run down (which condition will be indicated by an excessive dim¬ 
ming of the lights), that there is a loose connection in the starting 
circuit, or that the starting switch is not making proper contaet. 
The various tests previously given will probably take care of all 
these eonditions. 

Oiling of Starting Motor. The starting motor should be oiled 
once every 500 miles with any medium high-grade oil by applying oil 
to the eups, switch rods, guide rods, and pawl; also on the compensat¬ 
ing device. Starting motors equipped with the Bendix drive are 
fitted with oil cups at each end of the unit. 


ELECTRICAL EQUIPMENT 

U.S.L. SYSTEM 


493 


^ Twenty=Four—Twelve=Volt, and Twelve—Six=Volt; 

Single=Unit; Two=Wire 

Variations. The 24—12-volt signifies that the starting voltage 
is 24 and the generating voltage 12, the battery of twelve cells being 
divided into two groups of six each in series-parallel for charging, 
while 12—6 signifies that the starting voltage is 12 and the generat¬ 
ing voltage 6, the 6-cell battery being divided in the same manner. 

The foregoing systems will be found on cars prior to, and includ¬ 
ing, 1915 models. For 1916 and 1917 models, a 12—12-volt system 
of the same single-unit two-wire type is standard. In this system the 
complete battery is used for the lighting as well as the starting, so 
that charging, lighting, and starting are all at the same voltage, using 
the complete battery of 6 cells for both of the former. 

Qenerator=Starting Motor. The machine is multipolar (either 
six or eight poles) and is designed to take the place of the flywheel of 



Fig. 329. Details of U.S.L. Flywheel Type Dynamotor with Outside Armature 
Courtesy of U. S. Light and Heat Corporation, Niagara Falls, Neio York 


the engine. All but the 12—6-volt equipments are made with an 
outside armature. Fig. 329, i.e., the armature revolving outside of the 
field poles which it encloses; and the 12—6-volt with an inside arma¬ 
ture, Fig. 330. As the armature is mounted directly on the end of the 
crankshaft, the drive is direct at engine speed whether charging or 
starting. 






494 


ELECTRICAL EQUIPMENT 


One of the advantages of this type of machine, owing to its large 
size, is its ability to generate an amount of current far in excess of any 
ordinary requirement. This permits the employment in the inher- 



Fig. 330. U.S.Tj. Inside Armature Type Dynamotor 
(External Regulator) 

ently regulated type of only three brushes. Fig. 331, when the unit is 
running as a generator, while all the brushes are employed when it 

In the types equipped with an external 
regulator, all the brushes are employed 
for generating as well as for starting. 

Regulation. The 24—12-volt unit 
in the U.S.L. svstem is made with two 

V 

types of regulation, one type using an 
external regulator, which is usually 
mounted on the dash, and the other 
of the inherent type. The 12—6-volt 
type has an external regulator. These 
two types may be distinguished 
by the presence of the regulator 
in the charging circuit, which, how¬ 
ever, must not be confused with the 
automatic switch, or battery cut¬ 
out, which is only employed on the inherently regulated type. The 
details of the regulator are shown in Fig. 332, and it will be noted that 
the regulator also incorporates the battery cut-out as well as an indi¬ 
cating pointer which shows whether the regulator is working properly 
or not. In operation, the regulator cuts into the generator field 


operates as a starting motor. 

Top 



Fig. 331. Location of Generating 
Brushes in U.S.L. Dynamotor 






ELECTRICAL EQUIPMENT 


495 


circuit a variable resistance consisting of an adjustable carbon pile. 
The connections of the regulator are shown in the [wiring diagrams. 

The regidation of the U.S.L. inherent type is accomplished by 
the combination of a Gramme ring armature, a special arrangement 
of connections and of the field windings, and the use of only a part of 
the armature and fields for generating. This method is, of course, 
special on this make and could not be used on other types of construc¬ 
tion. The regulation obtained is based on armature reaction and is 
similar to that resulting from the third-brush method, but the machine 


Thrust Plate 



Charging 

Contacts 


Switch 

Lever 

Magnet 

Coil 


Switch Lever 
Spring 


Carbon Pile Lever 
Air Gap 


Adjustment Clamping Screws 


Indicator 


Carbon Pile 


Carbon Pile Lever 

pper Adjusting Plug 


Lower Adjusting Plug 


Fig. 332. External Regulator of the U.S.L. System 
Courtesy of U. S. Light and Heat Corporation, Niagara Falls, New York 


reaches its maximum output at a lower speed than would be possible 
with the third-brush method and without the employment of a 
special*brush for the purpose. 

Instruments and Protective Devices. In addition to the indi¬ 
cator, which is combined with the external regulator in the U.S.L. type, 
an ammeter is also employed to show the rate of charge and discharge. 

Two fuses, mounted in clips on the base which holds the bat¬ 
tery cut-out, or automatic switch, protect all the circuits. The 
smaller of these is a 6-ampere fuse and is in the field circuit of 
the generator, while the larger is a 30-ampere switch and is in the 
generator charging circuit. This applies only to those inherently 
regulated equipments fitted with a special type of automatic switch. 










49G 


ELECTRICAL EQUIPMENT 


Wiring Diagrams. Figs. 333, 334, and 335 show the standard 
wiring diagrams of the three types mentioned, being, respectively, 
the 24—12-volt externally regulated type, the 12—6-volt external 
regulator and internal-armature type, and the 24—12-volt inher¬ 
ently regulated type. In the diagram proper of each of the 24— 
12-volt types is indicated the layout for using 7-volt lamps, while the 
extra diagram at the side shows the method of connecting for 14-volt 
lamps. The ‘^touring switch” shown on the first two diagrams 
is a hand-operated switch in the charging circuit and is designed to 
prevent overcharging of the battery when on long day runs. The 
inherently regulated type requires very little field current, and on 
most of these the touring switch is of the miniature push-button type, 
like a lighting switch. 

Instructions. Touring Sivitch. On the types equipped with 
the touring switch, this enables the driver to control the charge. 
Pulling out the button closes the switch and permits the generator 
to charge the battery when the engine reaches the proper speed; 
pushing it in opens the circuit. This switch must always be closed 
before starting the engine, and it must be kept closed whenever 
the lights are on and also under average city driving conditions 
where stops are frequent and but little driving is done at speed. 
When touring, the switch should be closed for an hour or two and 
then allowed to remain open during the remainder of the day, as 
this is sufficient to keep the battery charged, and there is no need 
for further charging until the lamps are lighted. The best indication 
of the necessity for opening the touring switch is the state of charge 
as shown by the hydrometer. The driver should not start on a long 
day’s run with the battery almost fully charged, without first opening 
the touring switch, as the unnecessary charging will overheat the 
battery. This switch should be inspected at least once a season. 
Push in the button to open the circuits, remove the screw at the back 
and take off the cover. The switch fingers should be bright and 
make good contact with the contact block; if they do not do so, 
remove and clean them, as well as the contact pieces on the block. 
Do not allow tools or other metal to come in contact with the 
switch parts during the operation, for even though the switch is 
open, a short-circuit may result; then one of the fuses will blow. 
In replacing the fingers, bend sufficiently to make good firm contact. 



ELECTRICAL EQUIPMENT 


497 


REGULATOR 




e2-f 


<1 . 


82 - 


HEAO 


SIDE 


TAIL 

AND 

DASH 


F+ A+ 


■O-* 



AMMETER 


TOURING 

SWITCH 




f-r P ^ 

[ B+T B+ 

1 PrP 

g+Tg-^ 


J 







STARTING 

SWITCH 

(Generating 

Position) 


STARTING 

SWITCH 

(Starting 

Position) 


TAIL DASH 

7-VOiT lamps 


li^mT lamps 

Fig. 333. Wiring Diagram for 24—12-Volt_Regulator Type, U.S.L. System 

























































































































RfGUlATOR 


(—{JllillWD-] 

r-'lWWH' 


O (» II l> 


B2+ 


B2- F+ A+ 


TAIL ,, 

AND 

oashI 


TOURING 

SWITCH 




► < 

^ □ c 

r b+tb+ 

} 9.9 

g+Tg+ 



“ 

J 







STARTING 

SWITCH 

(Generatingi 

Position) 


STARTING 

SWITCH 

(Starting 

Position) 


T-VOLT lamps - 

P'ig. 334. Wiring Diagram for 12—6-Volt External Regulator Type, U.S.I,. System 


M 















































































































ELECTRICAL EQUIPMENT 


499 




U-S-L Starter and Lighter 
Wiring Diagram 

'24-12 Volt Inherently 
Regulated Type. 



Touring Switch 
G + 

-O O—, 


Head 


Side 


Tail r 
and 
Dash 


B2+ 

Battery 


Bl 


Bl- 


Oi 


-CH 


-y- 


0| 

o* 


y- 


-y- 


B-’t 


B2 


Bl 


Battery 

+ 


Head 


o 


Side 


Tail 


Bl 


Head. 


Side 


Dash 



-o 


-o 


o 


-o 











tQJ 

y. 

/ 


Starting 

Switch 


14-Volt Lamps 



Fig. 335. Wiring Diagram for 24—12-Volt Inherently Regulated Type, U.S.L. System 




































































































































ELECTRICAL EQUIPMENT 


r):K) 


StartitHj Stcifch. The starting switch is filled with oil, and this 
should be renewed once a year. To do this, the switch must be 
disconnected, and the screws A, Fig. 336, removed; in case the box 
sticks, insert a screwdriver point between the top of the box and the 
bottom of the frame and pry loose. To guard against the switch 
dropping when these screws are removed, hold the hand beneath it 
while taking them out. Before attempting to remove the switch, 
disconnect the positive battery connections and B2-\- at the 

battery as shown in Fig. 335. These are the two main terminals in 
the center. It is unnecessary to tape them, as a short-circuit cannot 
occur. Pour out the old oil, clean out thoroughly with gasoline, 
allow to dry, and refill with transformer oil or light motor oil to the 
proper level with the switch box standing plumb. The proper height 
on the Type E-2 or E-3 box is If inches, on E-4 box 2f inches. Before 

putting in the new oil, however, the 
drum and finger contacts should be 
examined, and, if pitted or dirty, 
should be cleaned with a fine file. 
Make sure that all fingers bear 
firmly against the drum so as to 
make good contact; if they do not, 
remove and bend them slightly to 
insure this. If the starting switch is abused in operation, or if improper 
oil containing water or other impurities be used, the contacts will 
burn and fail to make good electrical connection. The switch box 
is the only place in the system requiring oil. 

Brush Pressures. There is only one adjustment on the gener¬ 
ator, viz, the tension of the brush fingers. The brushes should fit 
freely in their holders so as to transmit the full pressure of the 
spring against the commutator. The adjustment as made at the 
factory should not need correction under one or two years of 
service. Pressures required on the various machines are as fol¬ 
lows: for Type E-12 external regulator, IJ pounds on each brush; 
IJ pounds on brushes of all other external-regulator machines; If 
pounds on each of the three lowest brushes on the inherently regulated 
type, these being the only brushes used in generating the charging 
current; If pounds on each of the remaining brushes of the inherently 
regulated generator. Keep commutator cFan, as the chief cause of 



m 


Fig. 336. U.S.L. Oil-Filled Starting 
Switch 





E r. ECTIII CAL EQUl PMENT 


501 


failure of the inherently regulated type is an excess of oil or dirt or 
both accumulating on it. 

Radial and Angular Brushes. The brushes employed are of two 
types—radial and angular. Radial brushes are used on external- 
regulator type generators other than those having “Type E-49” on 
the name plate; angular brushes are used on Type E-49 and all inher¬ 
ently regulated generators. Each radial brush should bear squarely 
against that side of its holder toward which the commutator rotates. 
Each angular brush should 
bear squarely against that 
side of its pocket away from 
which the commutator 
rotates. To sand-in old 
brushes or fit new brushes 
properly, insert a strip of 
No. 00 sandpaper (never use 
emery, paper, or cloth), be¬ 
tween the commutator and 
the brush, press down on 
top of brush and draw sand¬ 
paper under it. Fig. 337. If 
the brush is radial, draw the 
sandpaper in the direction 
of commutator rotation; if 
angular, draw the sandpaper 
in the direction opposite to 
that of commutator rota¬ 
tion. No oil is needed on 

the commutator as the Radial Brush 

, , , - , • . Fi". 337. Methods of Sandinff-In Brushes on 

brushes themselves contain Dynamotor 

all the lubricant necessary. 




Angular Brush 


Direction 
of Sanding;: 
In Brushes 


Direction' 
of Sanding 
in Brushes 


Direction of 
Rotation of 
Commutator 


Direction of 
Rotation of 
Commutator 


Fine sandpaper, as mentioned above, may be used for cleaning the 
commutator when necessary, the engine being allowed to turn over 
slowly during the operation. 

External Regulator. Should the automatic-switch (cut-out) 
member of the regulator remain closed with the engine stopped, 
start the engine at once, and the switch lever should open. If it 
does not, remove the regulator cover (with the engine running) and 









502 


EL ECn' R1E AL EQU1 PM ENT 


pull the lever open by hand. When the switch lever is correctly 
set, a slight discharge will be noted on the ammeter the moment 
the switch lever opens. This discharge reading should not exceed 
4 amperes; if in excess of this, increase the tension of the switch- 
lever spring by releasing the lock nut on the left side of the plate 
and turning up on the nut at the right until the proper adjustment is 
secured, then retighten the lock nut. The indicating pointer is moved 
by the switch lever in closing, and when it appears in its upper position 
through the sight glass on the cover, the battery is charging; when 
the switch lever opens, the pointer drops against its stop by gravity. 

When the battery shows a lack of capacity, the battery itself 
and all connections and fuses being in good condition, note the 
amount of charging current indicated by the ammeter. If the 
maximum current (external-regulator type) shown by the ammeter 
does not exceed 10 to 12 amperes at full engine speed after the 
engine has been running for fifteen minutes, see that the brushes 
and commutator are in good condition—wipe off the commutator 
with a dry cloth, and, if necessary, sand-in the brushes to a good seat. 
If this does not increase the generator output as shown by the 
ammeter, test the latter as already noted, i.e., see whether the pointer 
is binding and, if not, check with the portable testing instrument 
or another ammeter of the dash type. Should none of these reme¬ 
dies correct the fault, screw in the lower adjusting plug of the 
carbon-pile lever slowly, noting the effect on the ammeter reading 
as the adjustment is made. 

With the external regulator, the charging current should not 
exceed 18 amperes at the highest engine speed. If, at any time, 
the ammeter shows a higher reading than this, screw out the lower 
adjusting plug of the carbon-pile lever slowly to decrease the cur¬ 
rent, stopping when the indication does not go above 18 amperes 
at full speed. 

After making this adjustment of the lower plug, make sure that 
the carbon-pile lever air gap does not exceed | inch, and is not less than 
A inch when the engine is stopped. If the gap is too small the 
switch lever will vibrate rapidly at high engine speeds. When 
necessary to adjust this gap, screw the upper adjusting plug in or 
out, but, after doing so, the current output must be checked and 
adjusted by means of the lower adjusting plug. Always tighten 


ELECTRICAL EQUIPMENT 503 

the adjustment clamping screws after setting either of the adjusting 
plugs. 

Testing Carbon Pile. If the automatic-switch unit of the gener¬ 
ator does not cut in with the engine running at speed equivalent to 10 
to 14 miles per hour, test the carbon pile by short-circuiting the 
terminals F and yl-f- of the generator with the blade of a screw¬ 
driver. Speed up the engine slowly and note whether the generator 
cuts in much sooner than when the terminals are not short-circuited. 
Do not run the engine at high speed, nor for any length of time with 
the terminals short-circuited, as an excessive amount of current 
would be generated. If the generator does cut in much earlier 
with the terminals short-circuited than without this, the carbon ])ile 
needs cleaning. Should the generator not cut in earlier or should 
it fail to operate altogether, when the carbon pile is short-circuited 
the trouble is probably in the brushes of the generator or in the 
touring switch. 

To clean the carbon pile, proceed as follows: Unscrew the plug 
at the upper end of the glass rod and remove the rod; if any of the discs 
are pitted or burned, rub them together or against a smooth board to 
make them smooth and flat. Remove the end carbons and clean the 
brass plates with fine sandpaper, if necessary. In replacing end car¬ 
bons, make sure that they fit firmly against the brass end plates and 
that the screw heads do not project beyond the faces of the carbon 
discs. After reassembling the carbon pile, the regulator will need 
adjustment for current output, as previously noted. 

If for any reason it becomes necessary to disconnect the bat¬ 
tery, either open the touring switch and block it open so that it 
cannot be closed accidentally if the car is to be run, or disconnect and 
tape the right-hand regulator terminal A -f. Otherwise, the machine 
will be damaged by operating. 

Battery Cut-Out. Should either of the fuses mounted on the 
automatic switch of the inherently regulated type blow, immedi¬ 
ately open the touring switch. A loose connection or a short-circuit 
is probably the cause, and the touring switch should not be closed 
again until the cause has been located. 

Ammeter. The ammeter should be checked at least once a year 
by comparing it with a standard instrument, such as the portable out¬ 
fit mentioned previously, or any other suitable low-reading ammeter 


504 


ELECTRICAL EQUIPMENT 


of known accuracy. To do this, disconnect the positive wire from 
the ammeter on the dash and connect it to the positive terminal of 
the standard ammeter used for testing; then connect a wire between 



K 


TO 

U, 

C3 

o 

c 

o 

k—I 


c 

o 


TO 

>> 

zc 

zo 


6 

c; 

u 

to 

c3 

Q 

bO 


00 

CO 

CO 

hi 
• ^ 


the negative terminal of the standard ammeter and the positive 
terminal of the dash ammeter. With the engine running at various 
speeds, take simultaneous readings of both instruments; any differ- 






































































































































ELECTRICAL EQUIPMENT 


505 



Fig. 339. U.S.L. Type E-14 Starting Switch 


ence between the two should be taken into consideration thereafter 
when reading the dash ammeter. Unless a test of this kind is carried 
out, the battery may be receiving either an insufficient or an excessive 
charge while the ammeter indicates the proper amount. 

U.S.L. 12=Volt System. The U.S.L. 12-volt system generates 
and starts at 12 volts and is 
standard on the 1916 and 
1917 models of the Mercer, 

Fig. 338. It differs from the 
other systems in having a 
magnetically operated start¬ 
ing switch and a centralized 
control unit, which incor¬ 
porates all the controlling devices of the entire system, the cut-out, 
the ammeter, fuse blocks for generator and lighting circuits, starting 
switch, touring switch, head, side, and tail-light switches, all of 
which are operated by push buttons. All of these switch buttons, 
as well as the fuses, are locked in place, while the buttons may be 
locked in any desired combination of positions. 

Starting Switch. This is of the magnetically operated type and 
is mounted on the top of the field-mounting frame. It operates by 
means of a solenoid and 
plunger, as illustrated in Fig. 

339. Control is by means of 
a spring push button on the 
control unit marked‘‘ start”. 

Fig. 340. When this button 
is pushed in, it energizes the 
solenoid of the starting 
switch, which causes the 
plunger to close the con¬ 
tacts. Releasing the button 
on the control unit breaks 
the circuit, and the switch itself is then opened automatically by a 
self-contained spring. With this method of control, the current is 
only on as long as the starting button is held in. 

Fuse Blocks. There are two of these, the smaller, illustrated in 
Fig. 341, being the generator fuse block. This contains only two 



Fig. 340. 


U.S.L. Control Panel as Mounted on 
Dash of Mercer Cars 


























































































50G 


ELECTRICAL EQUIPMENT 






■r—^ 

^ ^ 


fuses, a large one 9 of 30-ampere capacity in the generator-battery 
charging circuit, and a smaller one 8 of 5-ampere capacity in the 
generator shunt-field circuit. Should either fuse blow, immediately 
push in the touring-switch button, as a short-circuit or an open or a 

loose connection is probably the cause. After 
locating the trouble, remove the generator fuse 
^ block from the instrument board. To do this, 
unlock the knob, press it inward, and turn ^ 
revolution to the right or to the left. Replace 
with spare fuses carried in the light fuse block, 
return the generator fuse block to its original 
position, and lock. 

The light fuse block, which is shown in 
Fig. 342, carries a total of seven fuses, of which 
four are in active use, while the remaining three 
are spare fuses for use in replacing blown fuses. On the right-side 
view of this fuse block there appear two large fuses 6 and 7. Fuse 7 
is a protecting link in the ground-return wire of the lighting and horn 
circuits. The small fuse 5 is of 10-ampere capacity and, together with 


-^ 

\ 

m 

1 

<9 






Fig. 341. U.S.L. Gener- 
at<^r Fuse Block 




Fig. 342. U.S.L. Left-Hand Side and Right-Hand 
Side Light Fuse Blocks 


fuse 6 of 30-ampere capacity, is a spare fuse for emergency use. On 
the left side of the block are three active fuses 1, 3, and 4 of 10-ampere 
capacity; and one spare fuse 2 of 5-ampere capacity. Fuse 1 is in the 
horn circuit, fuse 3 in the headlight circuit, and fuse 4 is common to the 
tail-, dash-, and side-light circuits. Should any of the fuses on this 
block blow, the trouble is probably a short-circuit on the frame of the 
car which should be remedied before the fuse is replaced. Instructions 


















































































































































































ELECTRICAL EQUIPMENT 507 

for the use of the touring switch in this system are the same as 
previously given. 

U.S. Nelson System. This type has been specially designed for 
the Nelson car, which first appeared in 1917, and it differs radically 
from those already described in that it is carried on the forward end 
of the engine crankshaft instead of at the rear. The brushes bear on 
the inside face of the commutator and may be reached through three 
openings in the armature support. To clean the commutator in this 
type, it is necessary to turn the armature so that three of the six 
brushes appear opposite these openings. Fold a small piece of sand¬ 
paper into a square over one of the brushes and allow the engine to 
turn over for a few minutes. Stop the engine and remove the sand¬ 
paper through one of the openings. The engine carries a flywheel at 
the rear, as usual, and this provision of flywheel weight at both ends 
of the crankshaft is said to minimize vibration almost to the vanishing 
point while making possible extremely high speeds. 

WAGNER SYSTEM 

Twelve=VoIt; Single=Unit; Two=Wire (Early Model) 

Dynamotor. The bipolar-type dynamotor has both the series 
and the shunt-windings, i.e., of generator and motor, connected 
to the same commutator. It is driven direct as a generator, and 
through a special planetary gear when operating as a starting motor. 

Regulation. The regulation is of the inherent type, utilizing 
the generator winding to weaken the field with increase in speed, 
i.e., a bucking coil. 

Wiring Diagram. Single-Unit Type. The left side of the 
lower half of the diagram. Fig. d43, illustrates the connections when 
the unit is being used as a starter, as indicated by the arrow showing 
the direction of rotation of the armature. Those at the right are the 
running connections, the armature then rotating in the reverse 
direction and generating current to charge the battery. 

Control; Transmission. Switch. This is a special type of 
drum switch mounted directly on the dynamotor on the same base 
with the battery cut-out. iVs shown in Fig. 344, when the lever Q 
is thrown to the left for starting, it also serves to tighten the brake 
band on the planetary gear. When moved in the opposite direction, 
it releases this brake, and another set of contacts on the drum of 


508 


ELECTRICAL EQUIPMENT 


the switch connect the generator for charging. Fig. 345 shows the 
details of this switch: A, B, and C are the contacts on the starting 
side, while H, G, and F are the running-position contacts, as shown 
in Fig. 343. The segments E and L on the drum contact with 


MEAD LIGHT MEAD LIGHT 



Fig. 343. Wiring Diagram for Wagner Twelve-Volt Single-Unit Two-Wire 

System (Early Model) 


the fingers mentioned when the drum is revolved part way in either 
direction by the lever, shown at the right, which engages the shaft M. 

Battery Cut-Out. This is of conventional design. For description 
and explanation of operation, see previous systems in which a battery 
cut-out, or automatic switch, is employed. Methods of locating 
trouble are given in connection with instructions farther along. 






























































































































ELECTRICAL EQUIPMENT 


509 




Fig. 345. Exploded View of Drum Switch. A, B, F, G, H, and K—Contact Screws to Contact; 
C—Auxiliary Contact Finger; E—Drum Contact; J—Screw Holding C; L—Auxiliary Drum 
Contact; M—Shaft 


TO Operating 
M Mechanism 


Fig. 344. Wagner Control Switch of Drum Type. A—Starter Frame; B—Switch Support; C— 
Outside End Plate Gear Box; D—Return Spring; F—Oil Hole Screw; G—Self-Closing Oiler; 
H—Oil Plug; J—Connecting Rod; K—Brake Band; M—Battery Leads; N—End Plate Screws: 
O—Back End Plate Shield; Q—Starting Switch Lever; R—Brake Band Lever; S—Front End 
Plate Shield 

Courtesy of Wagner Electric Manufacturing Company, St. Louis, Missouri 

H G F 






















510 ELECTRICAL EQUIPMENT 

Planetary Gear. The external form of the different gear boxes 
used on the early-model single-unit Wagner starter is the same, but 


Fig. 346. Exploded View of Planetary Gear Transmission. A—Planetary Pinion; B—Rolling 
Pawl; C—Center Pinion; D—Planetary Hub; E—Pawl Seat; F—Pawl Plunger; G—Internal 
Gear; H—Inside End Plate; J—Outside End Plate; K—Oil Plug; M—Sheet-Steel Disc 


Fig. 347. Assembled Planetary Gear. Letters same as Fig. 346 

their internal construction differs somewhat. The details of the 
two types employed are shown in Figs. 346 and 347. The prin¬ 
ciple employed is that of the planetary gear as used to obtain first, 










ELECTRICAL EQUIPMENT 


511 


or low, and high speeds on early-model light cars. The unit consists 
of a central, or snn, gear C, Fig. 347, and three planet pinions A 
meshing with the central gear and also with the internal gear ring G. 
For starting, the tightening of the brake band on the outer groove 
of the internal gear holds it fast, so that the drive is through the 
central gear and the reducing pinions in engagement with it and 
the gear ring, while, for running, the rollers B in the clutch D lock 
the gears together so that when generating the gear revolves idly 
as a unit. 

Instructions. The instructions previously given in connection 
with other systems apply here. For failure to generate, lack of 
capacity, grounds, or short-circuits in windings, and for keeping the 



Fig. 348. Jig for Holding Armature and Tooling Commutator 


commutator and brushes in condition, see instructions already 
given, as well as Summary of Instructions at the end of Part VIII. 

Method of Tooling Commutator. A different method of under¬ 
cutting the mica of the commutator is recommended from that 
already described in connection with the Delco system. This is 
illustrated in Fig. 348. The armature is removed from the generator 
and mounted in a simple jig, as shown. The jig is made of 1-inch oak, 
while ordinary machine screws held in place by lock nuts are utilized 
as the centers. The bar, or guide, on which the cutter operates, can 
be made of J-inch rolled-steel rod, while the cutter itself should be 
made of J-inch drill rod. The point of this cutter is ground sharp, like 
the parting tool used on a lathe or planer, to the thickness of the mica 
between the commutator bars. The cutter is moved backward and 




512 


ELECTRICAL EQUIPMENT 


forward on its guide in the same manner as a planer or shaper tool, 
and the armature is rotated one segment at a time to bring the mica 
sections under the tool successively. Where there is not sufficient 
work of this nature to make it worth while to build the jig, a simple 

hand tool mav be used. 


33 


C 


^Heavy Tin folded ground Too/ 




Section- 


Fig. 349. 


Diagram of Simple Hand Device for Tooling 
Commutator 


Fig. 349. This can be 
made of a discarded 
hacksaw blade or a new 
one, about 8 inches long. 
One of the ends is 
ground similarly to the cutter described for the jig, while the other 
should be shaped like a hook, having the same kind of point as the 
cutter end. Around the center of this tool should be folded a piece of 
heavy tin (sheet iron) and the whole wrapped with electric tape. This 
will prevent the brittle saw blade from breaking and make it much 
easier to handle. The mica is removed by forcing the sharp end of 
the tool from the outer edge of the commutator surface to the inner 
edge, and the rough cut thus made is finished by drawing the hooked 
end of the tool back through the groove in the opposite direction. 
To do the job properly, the armature should be held in a vise, other¬ 
wise it is liable to move, or the tool is liable to slip, and the copper 
be cut away with very poor results. Fig. 350 shows the commutator 

before and after under- 

BEFORE 


cutting the mica. 

A needle-p o i n t e d 
tool should never be used, 
as it will simply, make a 
V-shaped cut in the mica, 
removing too much in 
depth and not enough in 
width. The mica must 
be cut out clean and 
square, aiid a small mag¬ 
nifying glass should be 
used to see that all of the 
pieces adjacent to the bars have been removed. After removing the 
mica, the armature should be placed in a lathe, and a light cut taken 
from the commutators, i.e., just enough to remove all roughness 



AFTER 


Fig. 350. 


Diagram Showing Commutator Sections before 
and after Tooling 





























ELECTRICAL EQUIPMENT 


513 


and flat spots. The cutting tool employed should be very sharp, so 
that the soft copper will not be dragged from one segment to another. 
After turning, fine sandpaper should be used to smooth the commu¬ 
tator. W hether the brushes are replaced with new ones or the old ones 
are retained, they must be sanded-in to the commutator (see Delco 
instructions). The springs also should be tested for tension; they 
must never be allowed to become loose enough to permit the brushes 
to chatter when the generator is running, as this would interfere 
seriously with its output. 

Lack of Capacity through Faulty Gear Box. Should the battery 
not charge properly, note whether in starting the lights brighten 



Fig. 351. Method of Pulling Wagner Gear Box with a “Come Along” 
Courtesy of Wagner Electric Manufacturing Company, St. Louis, Missouri 


perceptibly with the car running below 5 miles per hour, while at 
high speed they remain dim. This indicates that the brake band of the 
gear box does not release, owing either to improper adjustment of 
the tightening screw or to something getting between the band and 
drum. To remedy, the band adjusting screw should be turned until 
the band feels free when the starting lever is in the running position. 
If something has caught between the band and the drum, its removal 
usually will be the only remedy necessary. 

Should the battery show signs of exhaustion, and if there is no 
noticeable increase in the brightness of the lamps when the car 
reaches a speed of 10 miles per hour or its equivalent, the trouble 






514 


ELECTRICAL EQUIPMENT 



probably is in the gear box. Remove the front end plate and note if 
the commutator is rotating. If not, and the reason therefor is not 
apparent on an inspection of the gears, it may be necessary to remove 
the gear box. A “come along”, such as is employed for taking off 
Ford wheels, is necessary for this. Fig. 351. It may be found that 
some of the parts need replacement, or that an entirely new gear 

box is necessary. 

Failvre Due to 
Battery Cut-Out. 1 f 
the failure to charge 
the battery be not 
due to the gear box, 
remove the cover of 
the cut-out and see 
if it is operating 
properly. When the 
engine is running at 
a speed equivalent 
to 15 miles per 
hour, the contact 
should spring away 
from the adjusting 
screw. If it does 
not, connect a volt- 
V meter across the 
terminals B and II 
of the switch. Fig. 
352. Should the 

Fig. 352. Details of Wagner Starting Switch. A and B—Large 

Contact Finger: C—Auxiliary Contact Finger; D—Auxiliary voltmeter needle 
Contact; E—Drum Switch; F, G, and H—Drum Switch Studs; 

J—Screw Leading to C; Q—Starting Switch Lever not mOVe, examine 

the contact fingers connected to the studs C and F and see that they 
make firm contact with the drum of the switch. Place the end of a 
pencil on the contact finger D and bear down lightly; if the main 
contact maker then springs away from the adjusting screw, the cause 
of the trouble is an open circuit at this contact. Bend D so that 
it bears down on the drum segments; should the contacts not close 
on making this test, the trouble will be an open connection, either in 
the generator itself or between the generator and the cut-out (switch). 










ELECTRICAL EQUIPMENT 


515 


Should the voltmeter give a reading of 6 volts while the contacts 
do not close, it shows that the shunt coil of the cut-out is open and 
indicates that its connections are broken or that the trouble is in the 
coil itself. This may be confirmed by operating the contacts by 
hand—pushing the contact away from the adjusting screw until it 
touches the stationary contact. If it remains in that position, the 
generator is charging the battery, but the shunt coil of the cut-out is 
out of action and the cut-out will function automatically as it shoukl. 

If, under the conditions mentioned in the first paragraph under 
this heading, the cut-out closes, connect the voltmeter as described 
and accelerate the engine to a speed corresponding to 25 miles 
per hour. If the reading is then 15 to 20 volts, the trouble may be 
looked for in a break in the generator connection to the cut-out. 
Should it not be possible to locate any break, it may be in the series 
coil of the cut-out, in which case a new cut-out will be necessary. 

Sicitch or Generator Parts to Be Adjusted. If the starting lever 
of the switch is not returning to the proper position for running after 
starting the engine, it will be indicated by a low battery and dim 
lights. Adjust so that the lever will go to correct position for running 
and see that the contact fingers of the switch are making proper 
contact with the drum. 

In case the battery does not get sufficient charge, connect an 
ammeter to the terminal D of the switch and to W of the cut-out. 
At a speed equivalent to 15 miles per hour, the ammeter should read 
7 to 9 amperes if the generator is working properly. If it does not, 
examine the commutator, brushes, and wiring, as previously described. 

Six=Volt; Two=LJnit 

General Characteristics. This type is similar in characteristics 
to most of the other makes of this class already described. 

Generator. The generator is the multipolar (four-pole) shunt- 
wound type. 

Regulation. The regulation is of the inherent or bucking-coil 
type, integral with the field windings of the generator. 

Starting Motor. The motor is four-pole and series-wound, driv¬ 
ing through a reducing gear mounted on the motor housing. Fig. 353. 

Control. Battery Cut-Out. The complete instrument, minus 
its cover, is shown in Fig. 354. It is of standard design and is intended 


516 


ELECTRICAL EQUIPMENT 


to be mounted in the tool box under the driver’s seat. As shown in 
the photograph, the upper binding post is the series-coil connection, 
the central binding post just below it is the shunt-coil connection. 



Fig. 353. Wagner Six-Volt Two-Unit Type Starting Motor. Left—Commutator 

End; Right—Gear End 

Courtesy of Wagner Electric Manufacturing Company, St. Louis, Missouri 



while the lowest binding post is a connection completing the circuit 
through both coils to the battery. 

Switch. The switch is of the circular knife-blade type, two sets 
of spring contacts close together being pressed down over the sta¬ 
tionary contact against the spring, as shown in Fig. 355 which illus¬ 
trates the parts of the 
switch. 

Wiring Diagram. A 

typical wiring diagram of 
the Wagner two-unit sys¬ 
tem as installed on the 
Scripps-Booth four- and 
eight-cylinder models is 
shown in Fig. 356. The 
only difference in the 
wiring of the two models 
has to do with the igni¬ 
tion and merely affects the distributor connections, as illustrated by 
the panel in the upper right-hand corner, which shows the distributor 
and connections for the four-cylinder car. As the system is a single¬ 
wire type, one side of every circuit is grounded, the spark plugs 
themselves representing the grounded side of the high-tension ignition 


Fig. 354. Wagner Cut-Out 






ELECTRICAL EQUIPMENT 


517 


circuit. The caution on the diagram —Never run geiierator 'with battery 
removed jroni car nor with tvire disconnected, from, generator —applies 
not only to the Westinghouse system but to practically every other 
system as well. 

Instructions. Ground in Starting or in Lighting Circuits. When 
the blowing of a fuse on one of the lighting circuits is due to a ground, 
or a similar fault is suspected in the starting system, it may be tested 
for either with the lamp outfit already described or with the low- 
reading voltmeter, as follows: 

I )isconnect one battery terminal, taping the bare end to prevent 
contact with any metal parts of the car, and connect one side of the 
voltmeter to this terminal. Attach a length of wire having a bared 
end to the other terminal of the voltmeter, as shown in Fig. 357. 



Fig. 355. Details of Wagner Switch 
Courtesy of Wagner Electric Manufacturing Company, St. Louis, Missouri 


Connect the bared end of the free wire to some part of the car frame; 
making certain that good electrical contact is made. Disconnect the 
generator and starting motor completely, open all lighting switches, 
and be sure that ignition switch is off. If there is no ground in the 
circuit, the voltmeter will give no indication. Be sure that none of 
the disconnected terminals is touching the engine or frame; to insure 
this, tape them. 

Should the voltmeter give a reading of 4 volts or more, it indicates 
that there is a ground in the wiring between the battery and the 
junction box, or in the wiring between the junction box and the gen¬ 
erator or the starting motor. If the voltmeter reads less than 4 





518 


ELECTRICAL EQUIPMENT 


volts but more than J volt, all wiring and connections should be care¬ 
fully inspected for faults. This test should be repeated by reversing 
the connections, that is, by reconnecting the wires on the side ol 
the battery circuit that has been opened and disconnecting the 
other side. 



Localizing Any Ground. To localize any fault that the reading 
of the voltmeter may show, reconnect the wires to the starting motor 
and close the starting switch; any reading of the voltmeter with 
such connections will indicate that the ground is in .this circuit. 
Should no ground be indicated with these connections, disconnect 





































































































































ELECTRICAL EQUIPMENT 


519 



the starter again and reconneet the generator; if the voltmeter 
records any voltage, the ground is in the generator circuit. With 
both starter and generator disconnected, the voltmeter being con¬ 
nected first to one side 
of the battery and then 
to the other, operate 
the lighting switches, the 
ignition switch, and the 
horn, one at a time, and 
note whether the volt¬ 
meter needle moves upon 
closing any of these 
switches. A voltage read¬ 
ing upon closing any of 
these switches will indi¬ 
cate a ground in that par¬ 
ticular circuit. 

Short-Circuit Tests. 

To test for short-circuits, substitute the ammeter for the voltmeter, but 
do not connect the instrument to the battery. The shunt reading to 20 


Fig. 357. 


Testing for Grounds with Voltmeter in 
Two-Wire System 



Fig. 358. Testing for Short-Circuits with Ammeter in Two-Wire System 

amperes should be employed, one side of the ammeter being grounded 
on the frame as previously described, and the other being connected 
with a short wire that can be touched to the open side of the bat- 





520 


ELECTRICAL EQUIPMENT 


tery, Fig. 358. Disconnect the starter and the generator and open 
all the switches, then touch the bare end of the wire to the battery 
terminal on the open side as shown. Any reading, no matter how 
small, will indicate a short-circuit (two-wire system) in the wiring 
between the battery and junction box or between the latter and the 
starter, or generator. If the ammeter reading shows a heavy current, 
there is a severe short-circuit. 

Localizing a Short-Circuit. The short-circuit may be localized 
in the same manner as described for the voltmeter test, i.e., connect 
the starter and test; disconnect the starter, connect the generator and 
test. A reading on the generator test may be due to the contacts of 
the cut-out sticking together. If the cut-out contacts are open and 
the ammeter registers, there is a short-circuit in the generator 
windings. 

Disconnect the generator again, remove all the lamps from the 
sockets, and turn on the lighting-circuit switches one at a time, touch¬ 
ing the wire to the battery terminal after closing each switch. A 
reading with any particular switch on indicates a short-circuit in the 
wiring of the lamps controlled by that switch. Only one switch should 
be closed at a time, all others then being open. This test should be 
made also with the ignition switch on but with the engine idle. The 
ammeter then should register the ignition current, wdiich should not 
exceed 4 to 5 amperes. If greater than this, the ignition circuit should 
be examined. 

Cautions. Do not attempt to test the starter circuit icith the ammeter 
as it will damage the instrument. To test the starter circuit, reconnect 
as for operating, removing the ammeter. Close the starting switch; a 
short-circuit in the wiring will result either in failure to operate or in 
slow turning over of the engine. See that the switch parts are clean 
and that they make good contact. If the short-circuit is in the wind¬ 
ing of the starting motor, there will be an odor of burning insulation 
or smoke. 

The battery must be fully charged for making any of these 
tests. While the effect either of a ground or of a short-circuit will 
be substantially the same, its location and the remedy will be more 
easily determined by ascertaining whether it is the one or the 
other. Instructions for making these tests have already been dis¬ 
cussed in the Gray & Davis section. 


ELECTRICAL EQUIPMENT 521 

WESTINGHOUSE SYSTEM 
Twelve=Volt; Single=Unit; SingIe=Wire 

Dynamotor. The single unit of the 12-volt system, or the 
“motor-and-generator” as the manufacturers term it, is a bipolar 
machine, both the generator and starting-motor windings of which 
are connected to the same commutator. Installation is usually by 
means of a silent chain, as on the Hupp (1915 and earlier). The 
characteristics of this type of machine are such that when running 
at a speed equivalent to 9 miles per hour or less, it acts as a motor, 
and when the speed increases, it automatically becomes a generator 
and begins to charge the battery. 

Regulation. The third-brush method of regulation is employed, 
the amount of current supplied to the shunt fields by this brush 


Shunt Field 



Fig. 359. Wiring Diagram for Westinghouse Single-Unit System on Hupmobile 


decreasing as the magnetic field of the generator becomes distorted 
owing to increased speed. 

Control. The switch employed with this type of combined unit 
is the regular single-throw single-pole switch used on lighting- 
plant switchboards. This switch controls both the ignition and 
the starting-motor circuits and, at starting, is thrown on and left 
closed as long as the car is running. 

Wiring Diagram. The connections of the Hupp installation 
are shown in Pfig. 359. 

Instructions. Battery Charging. As the unit acts as a motor 
to drive the engine when the latter is running at a speed of less 
than the equivalent of 9 miles per hour on high gear, slow driving 
or permitting the engine to idle at a very low speed when the car is 
standing will discharge the battery. Where no fault in the wiring 
or connections exists and the battery will not stay charged (the 































522 


ELECTRICAL EQUIPMENT 


generator, of course, working properly), this practice may be the 
cause of the trouble. If the voltage drops to 10 or 11 volts, with 
the headlights on but with the engine stopped, it indicates that the 
battery is practically discharged. This voltage reading will be 
somewhat higher in summer than in winter. The remedy is to 
run with fewer lights at night or to run the engine for longer periods 
in the daytime, or at higher speeds. Running solely at night will 
not keep the battery sufficiently charged, as most of the generator 
output is consumed by the lamps. Should the battery become 
discharged to a point where it cannot operate the starting motor, 
disconnect the wires C and S at the dynamotor, taping their ter¬ 
minals to prevent contact with any part of the engine or chassis. 
Start the engine by hand and, when running at a speed of about 
500 r.p.m., reconnect these wires, being sure to connect wire S first, 
when the battery will begin to charge. 

Fire Prevention. Gasoline or kerosene is frequently employed 
to wash automobile engines. Before doing so, be sure that the 
starting switch is open, and disconnect the negative terminal of 
the battery, taking care that it does not come in contact with any 
metal parts of the car. To make certain of this, it is better to tape 
the metal terminal. Allow the gasoline to evaporate entirely before 
reconnecting the battery, as a flash or spark would be liable to ignite 
the vapor. This naturally applies to all cars, although only such as 
are equipped with the Westinghouse single-unit or the Dyneto single¬ 
unit have starting switches which remain closed all the time the 
engine is running. 

Weak Currefit. If the dynamotor fails to operate when the 
starting switch is closed, open the switch and test with the port¬ 
able voltmeter. If it indicates less than 11 volts, the battery is run 
down; if it indicates 12 volts or over, look for a loose connection or 
an open circuit (broken wire) either in the connection from the 
battery to the starting switch, from the switch to the dynamotor, 
from the latter to the ground, or from the battery to the ground, in 
the order named. Dim burning of the lamps when the engine is 
stopped also indicates a discharged battery. When this is the case, 
it is advisable to recharge at once from an outside source, if possible. 

A quick method of determining whether there is a ground in the 
wiring is to disconnect the battery wire and, the engine being stopped 


ELECTRICAL EQUIPMENT 


523 


and all lights turned off, touch the disconnected wire to the terminal 
lightly. A spark, when this contact is made, will indicate a ground 
between the battery and the dynamotor or the switch. The testing 
lamp should then be used to locate the circuit in which the ground exists. 

Failure to charge properly may be due also to imperfect con¬ 
tact at the brushes or to a break in the shunt-field circuit of the 
generator, as explained in previous instructions. If the shunt-field 
circuit is found open, the trouble doubtless has been caused either 
by a ground between the battery and the generator or by running 
the generator when it was disconnected. 

To remove the brushes, lift the spring that holds the brush in the 
guide and take out the screw holding the brush shunt, when the brush 



Fig. 360. Westinghouse Bipolar Generator for Six-Volt Double-Unit Single-Wire System 
Courtesy of Westinghouse Electric and Manufacturing Company, East Pittsburgh, Pennsylvania 


can be slipped out. Care should be taken to replace brushes in the 
same position, and if they do not bear evenly over their entire surface 
on the commutator, they should be sanded-in as described in the 
Delco instructions. The latter suggestion also applies to new brushes. 

Six=Volt; Double=Unit; Single=Wire 

Generators. Four types of generators are made, as illustrated 
in Fig. 116, Part III; in Fig. 157, Part IV; and in Fig. 360, shown 
herewith, the fourth being similar to the unit shown on this page 
except for the method of regulation employed, which is of the third- 
brush type. 

Regulation. The reverse series-field winding, or bucking-coil, 
method is used in the first two types of generator, while a voltage 
regulator combined with the battery cut-out is employed on the 






524 


ELECTRICAL EQUIPMENT 




Closed 



Fig. 362. Closed and Open Position of Westinghouse Cut-Out Switch 

































































































































ELECTRICAL EQUIPMENT 


525 



Fig. 363. Wiring Diagram for Westinghousc System with External Regulator 













































































































520 


ELECTRICAL EQUIPMENT 


third, and the third-brush method on the fourth. This regulator is 
either self-contained, i.e., built in the generator, or is mounted inde¬ 
pendently. The connections of the built-in regulator are shown in 
Fig. 361. The open and closed positions of the contacts of the exter¬ 
nal cut-out are shown in Fig. 362. 

Wiring Diagram. Fig. 363 shows the connections of the separately 
mounted regulator together with the charging and lighting circuits. 



Fig. 364. Westinghouse Cut-Out Switch of Generator with Third-Brush Regulation 

Battery Cut=Out. The type of automatic cut-out used with 
the type of generator employing the third-brush method of regu¬ 
lation is illustrated in Fig. 364. This may or may not be combined 
with a starting switch mounted on the engine side of the dash or 
some similar location. Fig. 365 is a wiring diagram showing the con¬ 
nections of the separately mounted cut-out with the third-brush 
generator. The cutting-in speed varies from five to ten miles per 
hour on high gear, varying with the gear ratio and wheel diameter of 
the car. This speed may be determined by running the car slowly 
and speeding up very gradually, meanwhile observing the increase in 
speed on the speedometer. The point at which the contacts close 























ELECTRICAL EQUIPMENT 


527 


will be indicated by a slight quick movement of the ammeter needle. 
The cutting-out speed is slightly below this to preyent constant 



vibration of the cut-out armature when the car is being driven close 
to the cutting-in speed. 


























































































528 


ELECTRICAL EQUIPMENT 


Starting Motors. Variations. Several types are built to meet 
varying requirements; i.e., with self-contained reduction gearing, 
with single-reduction automatic screw pinion shift (Bendix drive), 
and with automatic electromagnetic pinion shift. The first two will 
be familiar from the descriptions already given of other makes. 
The third is similar in principle to the Bosch-Rushmore, but an 
independent magnet is employed instead of utilizing the armature 
of the motor itself for this purpose. 

Magnetic Engaging Type. This type, as well as the other types 
of starting motors mentioned, may be operated either by a foot con¬ 
trolled switch or by a magnetically controlled switch put in action 
by a push button: The wiring diagrams. Fig. 366, show the circuits 
of both installations and also make clear the operation of the auto- 



Fig. 366. Wiring Diagrams of Motor Connections for Automatic Electromagnetic Pinion Shift 


matic engagement. The armature is mounted on a hollow shaft; 
and on the end of this shaft is carried a splined pinion designed 
to engage the flywheel gear. This pinion is caused to slide along 
the shaft by a shifting rod which is attached to the pinion and passes 
through the hollow shaft. The other end of this shifting rod acts as 
the core of the shifting magnet and will be recognized as the plunger 
of a solenoid. When the motor is idle, a spring holds the pinion at 
the right-hand end of the shaft and clear of the flywheel gear. 

As shown diagrammatically in Fig. 366, when the starting switch 
is closed, the circuit is completed from the negative terminal of the 
battery, through the switch, the shifting solenoid, the armature, and 
the series field of the motor to the frame of the car on which the 
positive side of the battery is grounded. The large amount of 
current necessary for starting energizes the shifting solenoid suffi- 




















































ELECTRICAL EQUIPMENT 


529 


cieiitly to overcome the force of the spring so that it draws the shifting 
rod to the right through the hallow shaft, meshing the pinion with 
the flywheel gear. When the engine speeds up to the no-load speed 
of the starting motor, the current in the latter falls off so that the 
pull of the solenoid is less than that of the spring, and the pinion is 
automatically disengaged, though the motor will continue to revolve 
until the starting switch is opened. 

Electromagnetic Sivitch. In principle, the electromagnetic switch 
is the same as that of the automatic engaging device for the pinion. 
The movable double-pole contact, instead of being attached to a rod 
for foot operation, is mounted on the plunger of a solenoid and nor¬ 
mally is held open by a spring. This solenoid requires but a small 
amount of current for its operation and is connected on an independent 
circuit with the battery. It is controlled by a push button, and when 
the circuit is closed by means of the latter, the plunger of the solenoid 
is drawn into the coil against the pull of the spring, thus bringing the 
contacts together and holding them there as long as the solenoid 
is energized. 

Instructions. Regulator. When the generator of the voltage- 
regulator type fails to charge the battery properly, all parts of the 
circuit's and connections having been examined to determine that 
they are in proper condition, the regulator may be tested for faults. 
With the aid of the portable voltmeter, note at what voltage the 
contacts of the cut-out close or cut in, and at what voltage they 
cut out or open. See that the contact points are clean and square 
so that they make good contact over their entire surfaces when 
pressed together with the hand. Insufficient charging may be due 
to the voltage regulator keeping the voltage of the generator below 
the proper point for this purpose. A voltage adjusting screw is 
provided to compensate for this. With the voltmeter in circuit 
and the engine running, turn the screw very slowly and note the 
effect on the reading. For proper charging the latter should be 
approximately 7^ to 8 volts, and the screw should be adjusted very 
gradually to bring the voltmeter reading to this value. This screw 
is properly set at the factory and is unlikely to need adjustment; 
so all other possible causes should be investigated before changing 
it. The instructions for the 12-volt system also apply here, except 
that for voltage tests the system operates on 6 volts. 



FRONT VIEW OF HEINZE-SPRINGFIELD FORD STARTER MOUNTED ON CAR 

Courtesy of The John Heinze Company, Springfield, Ohio 










ELECTRICAL EQUIPMENT FOR 

GASOLINE CARS 

PART vn 


ELECTRIC STARTING AND LIGHTING 

S Y STEMS —(Continued) 


INSTALLING SPECIAL SYSTEMS FOR FORD CARS 

General Instructions. Most of the leading manufacturers who 
make the starting and lighting equipment for larger cars also manu¬ 
facture a special type designed for the Ford. Almost without 
exception these special Ford systems are simple and compact, and 
everything necessary to install them on the machine is provided by 
the maker of the apparatus. Where the system is to be installed, 
either by the owner of the machine or by the local garage man whose 
electrical experience is limited, the choice of the most suitable system 
often is decided by the ease with which it may be installed. In 
practically every case this necessitates the removal of the radiator, 
radiator brace rod, hose connections, fan, fan pulleys and belt, 
cylinder head, and in some cases the timing-gear housing. In the 
majority of instances the ground connection of the headlights— 
which is soldered to the back of the radiator on 1915 and subsequent 
models provided with electric headlights supplied by the Ford mag¬ 
neto—must be discarded altogether, as the lights are to be supplied 
by the storage battery. In cases where it is necessary to remove the 
timer (this must be done when the timing-gear housing has to be 
removed), both the timer and the carburetor should be adjusted for 
efficient running before starting to dismantle the engine, and if the 
latter is turned over while the timer is off, the ignition timing must be 
readjusted when the timer is put back. As the removal of all the 
parts mentioned is a simple matter fully covered in the Ford instruc¬ 
tion books and familiar to practically every garage man in the 
country, they are not repeated here. 





532 


ELECTRICAL EQUIPMENT 


In starting to install any system, one of the first precautions 
to take before attempting to dismount any of the parts of the engine 
is to check over the list of parts sent with the outfit with those 
actually received. The reason for this is that it at times an essential 
part has been omitted, and this is not discovered until a large part of 
the labor of dismounting the engine has been carried out; the work 
must be done all over again or the engine kept dismounted until 
the missing part arrives. 

QENEMOTOR 
Chain=Driven Type 

Mounting Starter. Drain the radiator and remove it with the 
water-pipe and elbow connections from the engine; remove the 
starting-crank claw and take out the starting crank; take the fan-belt 
pulley off the engine shaft, the fan and the supporting arm from the 
cylinder casting, the primer rod from the carburetor and timer- 
advance rod; take out the second and third right-hand crankcase 
bolts A, Fig. 367. Clean the engine thoroughly to insure proper 
seating of the bracket and with a file remove any high spots, or fins, 
on the casting that would interfere. Mount the unit on the engine, 
first inserting the base bolts and then the water-flange bolts with 
elbows. Place gaskets each side of the bracket. LTse the plain 
washers between the engine case and the foot of bracket B to insure 
proper support and alignment with the water-pipe connections E 
and F. Attach the driving sprocket G to the crankshaft, using the 
new pin H supplied. It may be necessary to bend the crankcase nose 
slightly at I to provide clearance for the chain on the right side and to 
chip off part of the rivet heads under the sprocket. There should be 
at least J-inch clearance at all points around the sprocket after the 
chain is in place. 

Replace the starting crank and claw and turn the engine over 
slowly by hand to feed the chain on to the sprocket. Connect the 
ends of the chain together, noting the arrows on the side of the chain, 
which show the direction in which it must rotate. Before connecting 
the chain, the Genemotor fan pulley with internal spring should be 
removed as a unit to prevent the possibility of changing the spring 
adjustment. Care should be taken that the slot in the spring support 
into which the forks of the pinion assemble clears the key. These can 


ELECTRICAL EQUIPMENT 


533 


be brought into line by holding the pinion and turning the fan pulley 
in a counter-clockwise direction (to the left). Loosen the clamping 



strap and tilt the whole unit slightly to receive the chain. Apply a 
straightedge, as shown in Fig. 308, and align the sprocket accurately. 




































































































































































534 


ELECTRICAL EQUIPMENT 


making sure that the Genemotor shaft is parallel with the crankshaft 
and that the pinion with bushing is pressed against the ball bearing. 
Allow a slight amount of slack in the chain when adjusting by means of 
the two set screws K, Fig. 367, which raise the unit in its cradle. 
When such adjustment is made, be sure that the starting switch is in 
an upright position on top of the motor and tighten the clamping 
strap. Grease the chain thoroughly and attach the chain guard L. 
Replace the pulley with spring locking with pinion, as when received. 

Assemble the clamp pulley 
supplied for driving the fan 
on to the regular fan pulley, 
reducing the flanges of the 
latter by filing, if necessary. 
Replace the fan and the 
bracket 0 on the engine. If 
the fan blades should not clear 
the Genemotor pulley, twist 
them slightly with a wrench 
and bend out the tips of the 
fan blades. Put back the old 
fan belt, but do not adjust it 
too tightly. Replace the timer 
rod, bending it as necessary 
to make sure that it clears 
the chain properly. Turn the 
engine over by hand to make 
sure that the chain is free 
and properly adjusted; it is 
important that the chain 
should not touch the nose 
piece or forward end of the crankcase or the side rivet heads. 
Before replacing the radiator and hose connections, it is advisable 
to run the engine a few minutes to note alignment, clearance, and 
operation. 

The dashboard is to be drilled for the lighting switch Q on the 
right-hand side, as viewed from the seat, directly under the carburetor 
adjustment and for the starting-switch rod R on the left-hand side 
close to the coil box. On the sedan, coupelet, and 1915 models, the 



Fig. .368. Method of Checking Chain Alignment 
with Straightedge 



















ELECTRICAL EQUIPMENT 


535 


lighting switch may be placed on the upper left-hand corner of the 
heel board under the driver’s seat, or it can be mounted on the dash 
close to the speedometer. Mount the primer lever and the special 
washer *S under the second manifold stud nut, passing the original 
rod through the dashboard. 

Wiring. All of the leads are marked for identification, and the 
wiring diagram will be readily understood from Fig. 369. The battery 
box should be mounted on the right-hand running board so as not to 
interfere with entrance to the car, and so that the hole in the bottom of 
the battery box overhangs the running-board shield, through which 
a new hole must be cut. The battery leads, protected by the circu¬ 



lar loom supplied for the purpose, should be run through this hole. 
The motor cables supplied with this outfit are to be run diagonally 
across the transmission case of the engine from the unit to the battery. 
Where they cross the transmission case, these leads are supported by 
a steel clip furnished for the purpose, the clip being secured under the 
right-hand screw holding the transmission cover in place (next to 
the dash). In installing the leads, the screw in question should be 
removed, the clip placed over the wires, and all secured by returning 
the screw through the clamp to its original position. The two 
hold-down straps are to fasten the battery box securely to the running 
board, the clamps fastening to handles of the battery case and passing 
through the running board. Where wiring passes through holes cut 




























































536 ELECTRICAL EQUIPMENT 

in sheet-iron parts, it should be protected by extra taping to avoid 
danger to the insulation from chafing. Make certain that all con¬ 
nections are clean, are properly made as shown on the wiring dia¬ 
gram-, and are clamped tightly. 

On the 1915 and subsequent models, on which the headlights are 
electric and are supplied with current from the magneto, it will be 
necessary to discard the wiring and switch connections and to do away 
with the ground connection soldered to the back of the radiator, as 



Fig. 370. Ford Frame Stripped for Mounting Shaft-Driven Genemotor 


the new system is of the two-wire type throughout, and all the lamps 
are fed with current from the storage battery through a lighting 
switch on the dash. 

Operation. The Genemotor is a single-unit type, the same 
machine performing the functions of both generator and starting 
motor. The starting switch and the reverse current relay, or auto¬ 
matic cut-out, are in a small housing mounted directly on the machine. 
Starting is elfected by pushing the switch rod forward. The switch 
will open automatically when the rod is released. During the first 
hundred miles, it will be necessary to watch the chain carefully and 



































ELECTRICAL EQUIPMENT 


537 


take up the slack as the links seat themselves in the sprockets. When¬ 
ever it shows excessive slack, the chain should be tightened so that 
it will not deflect more than f inch from a straight line by the pressure 
of the fingers. It is very essential to the life of the chain that it be 
not allowed to run too slack. The occurrence of any undue amount 
of noise in operation is a sign that the chain is too slack. The chain 
must always be kept sufficiently tight to prevent striking the 
guard or the nose of the crankcase and it is very essential that it 
be greased every two weeks. 


Shaft=Driven Type 

Preliminary Adjustments. Before dismantling the engine, be 
sure that it is in good running condition and that the carburetor is 
properly adjusted. Remove the radiator with the water-pipe and 
elbow connections, starting 
crank and claw or dog clutch, 
fan bracket complete with fan 
and belt, fan-drive pulley on 
crankshaft, timer or commu¬ 
tator complete, timing-gear 
cover (leave paper gasket 
and engine bolts A and rear 
sill bolt B, Fig. 370). Cut 
out the dashboard as shown. 

Remove the felt packing rings 
used around the crankshaft 
and camshaft from the old timing-gear cover, or housing plate, and 
place them in the new timing-gear cover supplied (sometimes referred 
to as the “cylinder front cover”). Reassemble, putting the new timing- 
gear cover in place, using bolts E, F, G, and H in the holes indicated. 
Fig. 371, and using lock washers. Leave the bolts slightly loose. 
Throw the hand-brake lever into middle position and push the crank¬ 
shaft back as far as it will go. Assemble the split hub J on the 
crankshaft, inserting the hub pin through a set of holes in the hub 
which give not less than and not over ^-inch clearance between 
the back of the hub flange and the timing-gear housing. 

Drive the hub pin K, Fig. 372, into the crankshaft, being careful 
that the ends are an equal distance below the surface of the threaded 



Fig. 371. Timing-Gear Cover Assembly 

































538 


ELECTRICAL EQUIPMENT 


portion of the hub. Chisel off parts of the rivet heads XX, Fig. 
373, in the pan of the engine and assemble gear ring L and place on the 
hub. In some cases it may be found necessary to bend out the side of 

the nose pan slightly by means of a wrench, as shown, to obtain 

the necessary clearance for the 
gear ring, which must not be 
less than inch at any point. 
The recess in back of the gear 
ring will facilitate its insertion 
past the front of the crank¬ 
shaft. Fasten the gear ring 
to the hub flange with the 
three screws and lock washers 
provided. 

Throw the hand brake in the extreme forward position to lock 
the engine and screw the hub nut M, Fig. 372, on the hub, tightening 
it with a |-inch steel rod inserted in the holes provided. Replace the 





Fig. 372. Fitting Split Hub on Crankshaft 



Fig. 373. Mounting Gear Ring and Adjusting Nose Pan in Genemotor Ford Installation 


starting handle minus its original starting ratchet, or dog clutch, using 
in its place the ratchet pin supplied, and retain it in place with the 
cotter pins N supplied. Fig. 372. Remove the leather coupling P, 



























539 


ELECTRICAL EQUIPMENT 


I^ig. 374, complete from the end of the pinion shaft. Unscrew the 
bearing-housing cap Q, Fig. 375, from the timing-gear cover and lay 



the bearing lining with pinion shaft in place. The coupling is keyed to 
the armature shaft and the drive shaft. Alicays remove the coupling 
coinplete hy driving it off either shaft. Do not separate the leather from the 












































































































540 


ELECTRICAL EQUIPMENT 



Fig. 375. Adjusting Driving Pinion 


be necessary. 


flanges. Be sure that the lining screw R, Fig. 375, in hearing the cap 
enters the hole in the hearing lining before replacing the cap, and that the 
shaft does not strike the base of the engine casting, which would spring 

the shaft. If necessary, 
file away the corner of the 
engine base to clear the 
shaft by at least ^ inch. 

Adjustment of 
Gears. The steel gear 
must at all times run on 
the fahroil teeth of the 
pinion and not on its steel 
shrouds. To accomplish 
this, rearrange the steel 
pacers S, Fig. 374, on the 
pinion shaft, placing them 
more or less forward or 
back of the lining, as may 
In no case should any washers be left out. Throw the 
hand-brake lever into middle position and turn the engine over with 
the crank, feeding in between the gears a strip of the paper T, Fig. 

375, supplied for the purpose. 
Lightly tap the timing gear to the 
left as far as necessary to mesh 
the gears tightly. Tighten up the 
retaining bolts. Turn the engine 
over again to feed the paper out. 
The paper should be evenly marked 
but not cut. If the paper shows 
signs of cutting through at any point 
the gears are meshed too tightly. 
Do not, under any circumstances, 
place any shim between the bearing 
lining and its supporting housing. 
Mounting the Qenemotor. Assemble the motor cradle in place. 
Fig. 376. Place a |-inch spacing washer under the leg nearest to 
the transmission cover and insert the special bolt A1 with the lock 
washer from the underside of the car but leave it slightly loose. 



Fig. 376. Motor Cradle Assembly ^ 















ELECTRICAL EQUIPMENT 


541 


Put in place the front leg bolt A and the new sill bolt B with lock 
washers but do not tighten up. Insert the Geneinotor from the rear 
side of the dash through the hole 
previously cut for the purpose, slid¬ 
ing it on to its cradle, and clamp in 
place with the steel strap, leaving 
about f-inch space. Fig. 377, be¬ 
tween the motor shaft and the pinion 
shaft. The flat space on the motor 
body should be parallel to the iron 
dash support. 

Motor Alignment. Raise the 
front leg and the sill leg of the 
cradle by a suitable thickness of spacing washers supplied until 
the ends of the shaft are in line, utilizing the clearance in the bolt 
holes to obtain the sidewise adjustment. The ends of the shafts must 
be lined up accurately to loithin inch, or the bearing ivill overheat and 
be destroyed. Check the line-up as shown in Fig. 377. When the 



Fig. 377. Checking up Alignment of Motor 
Shaft and Pinion Shaft 



Fig. 378. Priming Rod and Lever Adjustment 


adjustment is satisfactory, tighten all the bolts, setting up the lower 
nut on the sill bolt first and re-check the line-up; if necessary, 
































































































































































542 


ELECTRICAL EQUIPMENT 


readjust. Remove the bearing cap and the pinion shaft. Assemble 
the leather coupling on the pinion shaft, then assemble the other 
end of the coupling on the motor shaft; both should be a light drive 



Fig. 379. Layout on Under Side of Heel Board for Starting Switch and Cutout 

fit. Fill the recesses in the bearing lining and bearing with a good 
grade of non-acid grease. Replace the lining and shaft in the housing 
and secure the cap in place. Fill and fully compress the grease cup 
U twice to assure that the grooves and pockets are filled, Fig. 373. 
Also thoroughly grease the gears and assemble the gear guard with 
its two screws and lock washers. “Gredag No. 32-inch” (semi¬ 
liquid graohite grease) or its equivalent in powdered graphite lubri¬ 
cant is recommended for this 
purpose. 

Replace the Ford commu¬ 
tator, or timer, setting it with 
the steel brush upward when the 
exhaust valve of cylinder No. 1 
is closed, as mentioned in Ford 
ignition instructions. Fit the two- 
piece fan pulley around the neck 
of the Ford fan pulley and secure 
it with screws and lock washers 
provided. Reassemble the fan 
and bracket complete,using anew 
1-inch belt, which is driven from 
the pulley on the gear hub nut M, Fig. 372. Replace the radiator and 
the water connections to the engine, using a special bolt for the elbow 
connection nearest the genemotor. Replace the spark-advance rod, 



Fig. 380. Lighting Switch Mounted on 
Steering Post 
































ELECTRICAL EQUIPMENT 


543 


§ 

<0 


w c: 

^ 5) ^ 

0 N. C 

vj ^ ^ ^ 

^ :5 ^5 f'i:: ■■;: 

5<:iQ) 

^ Hw *W 


k: 

■K 



I 

<0 

::J^ 

■>J 


S-§ 

•-^ C ^ 

\i .^c: 

•K 

^ A» § ^ 




f\ Ss. ^ ^ 10 

'2'S:^ 1-^ 
k s 

I I I t I 


\ Cy^ rrj V^ 
«. •* .• •• ,. 






Fig. 381. Wiring Diagram for Head and Tail Lights 
Courtesy of General Electric Company, Schenectady, New York 






















































































































































544 


ELECTRICAL EQUIPMENT 


bending it to pass over instead of under the water connection, before 
fastening it to tlie timer. The throttle rod must be turned upside 
down and assembled with cotter pins toward the dash to clear the 
coupling. Attach the primer rod and lever, as shown in Fig. 378, 
using part of the Ford primer rod originally coming through the 
radiator. Mount the starting switch and cut-out on the underside 
of the heel board. Fig. 379. The rubber floor mat must be cut to 
fit the foot plunger. 

Mount the lighting switch on the steering column. Fig. 380, 
clamping the cable attached to it between the recess in the switch box 



Coui=e:let 



Fig. 382. Layout of Right Running Board for Mounting Battery Box 

on All Ford Models 

and column, and wire up the head and tail lights. Fig. 381, with leads 
supplied. Each lead is tagged to correspond with the wiring diagram. 
Drill holes in the right-hand running board for the battery box. 
Fig. 382, including the slot in the side panel where the main cables 
will pass through, and bolt the battery box on to the running board. 
Connect the Genemotor to the switch and cut-out. Fig. 381, placing 
on each battery cable a piece of the circular loom (supplied) at the 
point where the cables pass through the slot cut in the side panel, 
securing the circular loom in place by taping each end of the loom 





















































ELECTRICAL EQUIPMENT 


545 


to the cable. Each cable is tagged to correspond with the wiring 
diagram. Place the battery in the battery box, allowing it to rest 
on the wooden supports (supplied) and clamp through the box to 
the running board with battery clamps. Connect the negative lead 
to the negative terminal of the battery, then touch the positive 
lead to the positive terminal. If no spark occurs when the positive 
terminal is touched, connect up permanently; should a spark be 
noticed, it indicates a short-circuit or a leak in the system, and the 
wiring will have to be gone over carefully to correct it before con¬ 
necting up permanently, otherwise the battery will discharge itself. 
Turn the engine over slowly by hand to see that everything is clear. 
The starter and the lights are now ready for use. 

Operating Instructions. Whenever it is necessary to remove the 
battery for any reason, never operate the generator unless its terminals 
are first connected together with a copper wire or cable, otherwise the 
generator will overheat and injure its windings. The lights cannot 
be used with the battery off the car. Never operate the generator ivith 
the small regulating brush removed or toith its contact surface reduced, 
as normal charging current will not be generated, and the battery tvill 
not charge properly. 

In extremely cold weather, it is advisable to “break away” 
the engine by hand, giving the crank a few turns to loosen the lubri¬ 
cating oil on the pistons and bearings, thus preventing undue drain 
on the battery. The starter is designed to spin the engine at a speed 
sufhcient to insure easy starting on the Ford magneto. If the engine 
does not fire promptly, pull out the priming rod at tiie forward end 
of the radiator and turn the engine over two or three times by hand 
before closing the starter switch again. Should the engine still fail 
to start, examine the timer, squirting a liberal supply of one-fourth 
kerosene and three-fourths lubrication oil into it; see that there is 
plenty of gasoline in the tank and that it is reaching the carburetor. 
Turn the carburetor, or gasoline-supply adjustment, on the dash up 
(to the left) to insure a liberal supply of gasoline in cold weather. 
When an easy starting point of this adjustment has been found, it 
should be marked by filing a nick or arrow on the small brass wheel; 
turning the latter with the arrow upright will then insure easy 
starting in cold weather. After the engine has run a short time and 
become warmed up, the wheel can be turned down 15 to 20 


546 


ELECTRICAL EQUIPMENT 


degrees (to the right), and several more miles per gallon will be 
secured. When the engine does not get under way promptly, do not 
exhaust the battery unnecessarily by continuing to run the starter. 
In any case where the engine fails to start the first time and exami¬ 
nation shows everything to be in good condition, operate the starter 
intermittently a few seconds at a time but not continuously. 

Failure to Start. When the starter fails to turn the engine 
over, try cranking by hand to make sure that the crankshaft is free 
to revolve before attempting to make any adjustments. If it turns 
freely by hand but the starter cannot move it, test the condition of 
the battery charge with the hydrometer. In winter, particularly, 
cars are often run for days at a time on very short runs with frequent 
stops and starts, and under such conditions the battery is likely to 
become exhausted, as the average charge is less than the requirements 
imposed upon it by the great number of starts made. In such cases, 
it may be necessary to give the battery a special charge from an 
outside source or by running the engine with the car standing. 

Ammeter. A recording instrument is not regularly supplied as 
a part of the system, since the generator is fitted with an inherent 
type of regulation having no moving or vibrating parts, so that as 
long as the system is kept in good condition, charging is assured. 
Where the owner considers the addition of an ammeter desirable as 
a means of checking the operation of the system, the instrument 
can readily be added by removing the jumper wire on the starting 
switch and connecting the ammeter leads across these two posts. 
The lamps recommended for use with the system are 12- and 14-volt 
15-c.p. Mazda or 24-c.p. nitrogen (not desirable, as it causes too 
much glare), and 12- and 14-volt 4-c.p. Mazda for the tail light. For 
care of battery, see sections on Battery Charging and Maintenance. 

GRAY & DAVIS 

Installation. Preparing Engine. Remove the radiator, discon¬ 
necting the ground wire from it; disconnect the wires from the head 
lamps and remove the head lamps and supports. Take off the bracket 
and fan. Fig. 383, and turn the engine by hand until the pin 2 in the 
fan pulley is straight up and down; remove the pin from the jaw 
clutch and remove the starting-crank 4, belt 6, and the cotter pin, 3; 
take the pin from the fan pulley and remove the pulley 6. Remove 


I 


ELECTRICAL EQUIPMENT 


547 


the second, fourth, and fifth bolts from the crankcase flange 7, the 
left and front bolt from the side-water connections 8 and 9, as well 
as the second cylinder-head bolt 10. 

Note The numerals refer to the parts to be removed or replaced, as well 
as the sequence in which the operations are to be carried out, as shown on the 
sketches. Each illustration, however, has its own series of the same numbers, 
which should not be confused with those on other views. 

Lay the chain 1 in the rear of the engine support around the 
crank-shaft. Fig. 384, and then place the original starting-crank jaw 



Fig. 383. Preparing Engine for Mounting Starting Unit 
Courtesy of Gray & Davis, Boston, Massachusetts 


clutch ^ inside of the crankshaft sprocket. Place the crankshaft 
sprocket 3 on the crankshaft and put the new belt 4- around the pulley 
on the crankshaft. Secure the sprocket with the new pin 5 (supplied) 
and then connect the starting crank in its original position. Secure 
the jaw clutch to the starting crank with pin 7. 

Mounting Starter-Generator. In Fig. 385 is shown the starter- 
generator unit, for which note the following instructions: See that 











































































































































































548 


ELECTRICAL EQUIPMENT 



Fig. 384. Putting Driving Chain on Crankshaft Sprocket in 
Cray & Davis Ford Installation 



Fig. 385. Details of Gray & Davis Generator Unit for Ford Starter 




























































































































































ELECTRICAL EQUIPMENT 


549 


the motor terminal 1 is free from contact with any other metal; also 
that the dynamo terminal 2 and insulation are not injured. Test the 
shaft and gears 3 to see that they turn freely, and then fill the oil 
cups 4 with oil. 

Release the top adjusting screw 5, also two lower clamping lock 
nuts 6 (front), as well as the two upper clamping lock nuts 7 (rear) and 
the single middle clamping lock nut 8 (front). The units must be in 
the lowest position possible on the bracket before placing it on the car. 
In Fig. 886 is shown the starter-generator unit in place on the engine 
with the bolts and nuts all tightened. This is carried out as follows: 



Fig. 386. Starter Unit Mounted on the Engine 
Courtesy of Gray & Davis, Boston, Massachusetts 


Place three |-inch spacers over the first, second, and third holes in 
the crankcase flange 1, and then place the unit on car 2; pass three 
f- by 2|-inch bolts through the lower bracket, but do not attach nuts 
3. Tip the starter unit forward and pass the chain over the dynamo 
sprocket 4; attach the bracket by meams of cylinder-head bolt, but 
do not fasten. 

Place a ^-inch spacer between the bracket and top water con¬ 
nection 7 and attach the bracket with by 2f-inch bolts, but do not 
fasten securely; then place sVinch spacers 7A under the bracket 





























550 


ELECTRICAL EQUIPMENT 


so that the chain will be tight when the units are in the lowest possible 
position. Use washers 8 as shims between the bracket and the 
cylinder-head link. Secure the three lower bracket bolts 9 with 
lock washers and nuts, also secure the water-connection bolts 6 and 
7 and the cylinder-head bolt 5. Adjust the bracket stay bolt 10, 
adjust the chain 11 to moderate the tension and lock adjustment, 
securely tighten five clamping bracket nuts, and then crank the engine 
slowly by hand to see that everything turns smoothly. If, through 
some irregularity in the engine casting the bracket should not seat 
properly, it may be necessary to file the bracket holes to meet this 
condition. Be sure that the sprockets are in true alignment, or the 



Fig. 387. Installing Gray & Davis Wiring and Lighting Switch on Ford Car 


uneven strain may cause injury. If necessary, elongate the holes in 
the bracket or shim bracket as needed to insure perfect alignment 
of chain. 

When adjusting the bracket stay bolt 10, make sure that it rests 
against the engine casting without strain and secure it with nuts on 
each side of the bracket. Bend the ignition timing to clear the chain, 
if necessary, but after bending, the distance between the ends of the 
rod in a straight line must be equal to its original length. Adjust the 
chain to moderate tension and secure both the adjustment lock nuts 
at the top. If all five nuts holding the adjustable bracket are not 
released before adjusting, uneven strain may cause injury. Securely 




























































ELECTRICAL EQUIPMENT 


551 


tighten the sliding-bracket nuts two at the bottom front side, 
two at the top rear, and one at the front end. Test by turning the 
engine over by hand slowly. 

Remounting Engine Parts. Fit split pulley 1 to the hub of the 
fan. Fig. 387, and attach split pulley 2 with four screw^s; slip a new 
belt over the fan pulley, attach the fan, and adjust. Place the radia¬ 
tor 4 on its support and screw the radiator rod into the radiator and 
secure with check nut 3; secure the hose clamps at the top and side 
water connection 6; place the radiator nuts and secure with cotter 
pins. Attach the lighting switch at the cowi (left) with j^-inch screws 
and attach three lighting- 
cable clips on the rear of 
the dash, using ^-inch 
wood screws; cut the 
corner from the toe board 
for clearance. Attach 
three wire clips 10 to the 
left side of the frame and 
attach green wire 11 to 
the dynamo terminal. 

Then connect [the short 
black and red wire to the 
left head lamp. Pass a 
long black and red wire 
through the radiator tube 

to the right head lamp, Fig. 3 S. installation of starting Switch 

. , , 1 1 , Courtesy of Gray & Davis, Boston, Massachusetts 

then connect the short 

wire from each head lamp to the metal of the car frame 14- Attach 
the starting cable 15, which has a copper terminal at each end, to the 
starting-motor terminal. Refill the radiator and w^atch carefully for 
leaks in the circulation system. 

Starting Switch. The location of the starting switch and the 
method of installing it are shown in Fig. 388. Take the plate 1 off 
the starting switch and use it to mark the holes in the fioor strip two 
inches in front of heel board and nine inches from the sill, as shown in 
the illustration. Make three holes for the starting switch in the rear 
floor strip 2 and attach the switch with bolt 3 at the side nearest the 
center of the car; then attach the other switch bolt 4> support 






























552 ELECTRICAL EQUIPMENT 

the cable clip holding the two wires, and secure the spring and the 
knob with a pin. 

Priming Device. Connect the priming device 1, h'ig. 389. Drill 
a ^Vinch hole in the dash two inches to the right of the coil box and 
six inches above the toe board and pass the upper rod through. Con¬ 
nect the lever arm 2 vertically to the foremost exhaust manifold bolt 
with stationary member in horizontal position; then connect the lower 
rod 3 to the carburetor priming lever. Work it back and forth several 
times to make sure that it returns to normal position when released. 

Battery. Place the battery box on the right-hand running board, 
Fig. 390, to permit easy opening of doors and access to battery box; 



Fig. 389. Replacement of Carburetor Timing Rod on Dash 
Courtesy of Gray tt Davis, Boston, Massachusetts 

then mark four holes with the center punch. Drill four holes ^ inch 
in diameter in the running board 2, using a jack or prop to support 
the running board while drilling. Replace the battery box on the 
running board in order to mark the holes in mud guard for insulating 
cable bushings 3, then make two holes If inches in diameter. Insert 
insulating-cable bushing 4- in left hole and secure with round wooden 
nut; do the same with the right-hand bushing 5. Secure wood nuts 6 
with a wire twisted around the thread. A coat of heavy paint will 
also hold the nut in place and preserve the insulator. Place the two 
flat wood cleats 7 with holes at each end between the battery box and 
the running board; then pass four bolts 8, f inch by 1J inches, through 















ELECTRICAL EQUIPMENT 


553 


the battery box, cleats, and running board, and secure them with 
four nuts and lock washers. Place two special-shaped wood cleats 9 
inside the battery box, one at each end for the battery to rest upon, 
so that holes in the cleats will fit over the bolt heads. Raise springs 
10 and hang on the side of the battery box, placing the battery in the 
box and inserting two J-inch wood strips, one each side between the 
battery and the battery box. Attach two springs 11 at opposite ends 



Fig. 390. Installing Gray & Davis Battery and Wiring 


to hold the battery down securely. Inspect the battery and if the 
solution does not cover the plates at least ^ inch, add pure water, 
filling the cells to f inch above the tops of the plates. Water for 
battery use should be free from iron or alkali. 

Final Connections and Adjustments. Fig. 391 is a plan view of 
the chassis, showing the entire system in place. Figs. 392 and 393 
show the wiring in plan and in perspective. Drill and attach to the 
woodwork on the underside of the body 1 three wire clips holding the 





























Fig. 391. Plan View of Complete Wiring System for Gray & Davis Ford Installation 
Courtesy of Gray & Davis, Boston, Massachusetts 
























































































































555 


ELECTRICAL EQUIPMENT 

tail-light wire; see that the wire does not make contact with any metal 
edges. Attach the electric light 2, If the tail lamp has a one-point 
wire connector, the lamp body must be metallically connected with 


:?V 







i 

.•i': 


BATTERY 



GREEN 
RED 









GROUNDS TO 
TRANSMISSION 


• STARTER CABLE 




LIGHTING 

SWITCH 


CUT OUT y 
POINTS/ 

r-i--. 'rd-^ 



BLACK 

GREEN 



BLACK OR 
BLACK AND 
YELLOW 


RED AND 
BLACK 

CUTOUT 


Fig. 392. View of Complete Wiring System Simplified 


the chassis frame. Be sure the connecting surfaces are clean, free 
from paint, and securely connected. Connect the tail-light wire 3 
to the tail lamp. Tail lamps are usually made with a single wire 
connector, but, if the lamp has two wire connectors, another wire 





















































556 


ELECTRICAL EQUIPMENT 



o 

2 

CQ 

a: 

o 



should run from the .second 
terminal of the connector to the 
metal framework of the car. 
Connect the short starting 
cable 4 (negative) and the 
green and red wire to the start¬ 
ing-switch terminal nearest the 
battery. Then pass the end of 
the battery cable through the 
foremost insulator 'in the mud 
guard. Attach the end of the 
starting cable 5, leading 
through the rear hole in the 
mud guard, to the second bolt 
in the transmission case. Use 
a lock washer and a plain 
washer under the head of the 
bolt to insure permanent con¬ 
tact. Connect the long bat¬ 
tery cable (positive) to the sec¬ 
ond transmission bolt and 
secure with a plain washer and 
a lock washer. Then pass the 
end of the cable through the 
rear insulator in the mud guard. 
Attach to the starting-switch 
terminal 6, securely, the end 
of the cable which runs to the 

L 

starter. Support the starter 
cable 7 by a clip to the inside 
curved edge of the dash. When 
connecting cables to the bat¬ 
tery, be sure that the terminals 
are securely fastened—firm 
contact must be made. The 
battery terminals are made of 
lead and must be handled care¬ 
fully. Battery-cable terminals 





























ELECTRICAL EQUIPMENT 


557 


differ slightly in size and correspond to the holes in the battery 
terminal, the negative-cable terminal being the smaller. Pass the 
foremost cables 8 through the battery-box insulator and connect 
them firmly to the negative battery terminal. Do not connect 
the positive cable to the battery or insert the fuses until the instal¬ 
lation has been made in accordance with the instructions and tests 
show that wires are not in contact with the frame of the car. Turn 
the lighting switch off and touch the positive terminal lightly to the 
battery terminal. If there is a spark, it indicates a short-circuit or 
a ground, caused by a wire coming in contact with the frame. 
Remedy the trouble before connecting up the battery. If there is 
no spark, permanent connection may be made. The lamp-test set 
may be used to determine 
whether there are any 
grounds or short-circuits, 
before connecting up the 
battery. 

When all indications 
show that the installation 
has been made properly, 
connect the positive start¬ 
ing cable to the positive 
terminal 9 of the battery. 

Place and secure the 
cover 10 on the battery 
box. Place fuse 11 \n fuse clip of lighting switch. Fig. 394 shows 
details of the different types of lamps. 

Instructions. Oil the two generator bearings and the two motor 
bearings every 200 miles, keeping oil-well covers closed The chain 
must be kept w^ell adjusted. When the unit is first installed or when 
a new chain has been fitted, the chain should be adjusted occasionally 
during the first 500 miles of travel until all stretch has been taken 
out of it. After this distance has been run, the chain stretch will 
be slight. Never allow the chain to run slack. 

To adjust the chain, release five clamping nuts (2 nuts in the rear 
of the bracket at the top, 2 in front of the bracket at the bottom, and 
1 at the right-hand side) a few turns to permit the bracket to slide. 
Then adjust the chain to moderate tension by turning the adjusting 



Fig. 394. Details of Gray & Davis Ford Lamps 

































558 


ELECTRICAL EQUIPMENT 


screw at the top of the bracket and tighten the check nut and adjust¬ 
ing screw to lock the adjustment. Then retighten all five clamping 
nuts securely. Turn the engine by hand to determine whether the 
chain runs smoothly; the chain should not be too tight. After long 
service, when all chain adjustment has been taken up, the chain may 
be shortened by taking out a pair of links. The latest type of chain is 
supplied with a removable pair of links, retained in position by two 
removable pins. These pins are a trifle longer than the regular 
riveted pins. 

Where the chain has been shortened, it is sometimes necessary 
to lower the supporting bracket slightly by removing some of the 
^-inch washers under the bracket or by filing the spacers slightly, so 
that the chain will be tight when the unit is in the lowest possible 
position. 

Wires are subject to dislodgement and injury, hence they should 
be examined carefully to see that they are not resting on sharp edges 
of metal and that the insulation is not worn or injured. See that none 
of the wires are swinging or rubbing against metal, as this is likely to 
injure the insulation. Also examine the cables leading through the 
battery box and mud guards; the bushings must be intact and in place 
to protect the cables from short-circuiting. Wherever injury to any 
part of the insulation is found, wrap the spot carefully with insulating 
tape and bend away from the metal to provide sufficient clearance to 
prevent further damage. 

If the lamps fail to light when the lighting switch is operated, 
the fuse on the back of the lighting switch should be examined; it may 
be burned out, broken, or not properly clamped in its fuse clips. 
The wires may not be properly connected (this should be checked by 
wiring diagram), the bulbs may be burned out, or the filaments may 
be broken. The lamp wiring may be short-circuited or the charging 
circuit may be open. 

Do not run the engine with the battery disconnected or off the 
car without first insulating or removing two of the generator brushes 
to prevent the generator from generating a current. To determine 
if generator is operating properly, turn on the head and tail lamps 
while the engine is idle. Start the engine and accelerate to charging 
speed or over; a perceptible brightening of the lamps will indicate 
that the machine is generating sufficient current both to charge the 


ELECTRICAL EQUIPMENT 


559 


battery and to light the lamps. Do not open the charging circuit at 
any time when the engine is running. 

Testing Generator with Ammeter. A more accurate determina¬ 
tion may be made by connecting an ammeter in the circuit. Discon¬ 
nect the red and green wire connected to the fuse terminal on the back 
of the lighting switch and connect it to one terminal of the ammeter. 
From the other terminal of the ammeter, connect a wire to the fuse 
terminal to which the red and green wire was previously connected. 
Turn the lights on with the engine idle. The ammeter should regis¬ 
ter “discharge”, the reading representing the amount consumed by 
the lamps turned on, i.e., head and tail lamps, 5 to 6 amperes; side and 
tail lamps, IJ to 2 amperes. If the ammeter indicated “charge” 
instead of “discharge”, with the lamps turned on and the engine idle, 
reverse the wires connected to the ammeter terminals. In case the 
ammeter does not register, see that the pointer is not jammed, other¬ 
wise, the circuit is open at some point or the battery is exhausted. 

Run the engine at a speed corresponding to 12 to 15 miles per 
hour, the lights being turned off. If the ammeter registers “charge”, 
the generator is then charging the battery. Increase the engine speed 
to a car speed corresponding to 13 to 18 miles per hour. The ammeter 
reading should then be from 12 to 15 amperes. As the engine speed 
is increased above 18 miles per hour, the charging rate will decrease 
gradually to approximately 10 amperes at very high speed. With the 
engine running at 12 miles an hour or faster, turn the lights on; 
the charging rate should drop according to the number and size of the 
lamps turned on (see current consumed by each lamp as given above). 
Turn the lights off and, while permitting the engine to slow down, 
observe the ammeter. It should drop to zero at approximately 0- 
to 2-ampere charge. 


HEINZE=SPRINQFIELD 

Preliminary Operations. Before beginning the installation, 
adjust the ignition and the carburetor so that the engine is working 
efficiently. Remove the radiator and the radiator tie rod; disconnect 
the water-inlet pipe from the side of the cylinder, but do not break the 
hose connection; also disconnect the water-outlet pipe from the upper 
forward end of the cylinder block. Remove the priming wire that 
protrudes through the front of the radiator and is connected to the 


560 


ELECTRICAL EQUIPMENT 


carburetor; disconnect the wires from the headlights, first removing 
the plugs from the sockets; and disconnect the wires from the connect¬ 
ing plugs. The radiator can now be lifted from the frame. After 
it has been removed, disconnect the water-outlet pipe Irom the hose 
and discard the latter. Remove and discard the ground-wire connec¬ 
tion of the Ford lighting system, which will be found soldered to the 
lower left-hand corner of the back side of the radiator. 

Remove the fan and the starting crank and the fan pulley. 
To take off the pulley, first remove the two cotter pins from the pin 
holding the fan pulley on the end of the crankshaft. Throw the speed 
lever in gear (allowing it to go forward to engage the clutch) and push 
the car forward or backward enough to turn the motor over so that 

the pin is in a vertical 
position, Vhich will per¬ 
mit driving the^pin down 
through the hole in the 
engine frame. Then re¬ 
move the fan pulley and 
discard it with [its start¬ 
ing pin and cotters. 

Disconnect the ad¬ 
vance rod from the timer 
case, placing the rod to 
the right to keep it out of the way of subsequent operations. Take 
out the cap screw running through the breather pipe. This will 
release the spring holding the timer housing in place, and the timer 
housing can be lifted off. Place it to the left, hut do not disconnect the 
wires. Note carefully the position of the timer, or commutator¬ 
brush assembly, and then remove it from the camshaft by taking off 
the nut, the small steel brush cap, and the retaining pin holding the 
brush assembly to the shaft. Do not turn the motor over while the 
timer brush assembly is off, and he sure to replace it in its original 
position when reassembling. In this way the timing of the engine 
will not be deranged. 

The timing gear, or cylinder front cover, should then be removed, 
retaining all the bolts, the nuts, the gaskets, and the cotter pins, for 
replacement in mounting the main-bracket plate 785 of the Heinze 
equipment, Figs. 395 and 396. It is necessary that the felt washers 



Fig. 395. Correct Assembly for Belt Tightener for 
Heinze-Springfield Ford Installation 




























ELECTRICAL EQUIPMENT 


561 



a 

’3) 

a 

W 

’TS 

o 

C3 

o 


T3 

(U 


o 

►se 

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562 


ELECTRICAL EQUIPMENT 


in this timing-gear cover around the crankshaft and the camshaft 
be removed and inserted in the corresponding positions on the new 
main bracket plate which takes the place of this cover. In case the 
car has seen considerable service and these felt washers are worn, it is 
advisable to replace them with new ones; otherwise, there will be a 
dangerous leakage of oil from the crankcase. 

Secure the water-outlet header 834, Fig. 396, in place on the 
cylinder-head casting, using the original Ford bolts and gasket. 
Place the fan-belt tightener 865, Fig. 395, with the nose away from the 
large gear housing, in the slide provided for it on the main bracket 
plate 785. Remove the fan-adjusting screws and the locking nut 
from the Ford timing-gear housing plate and use them together with 
the two lock washers (9X10) and the plain washer (2X48), as shown 
in Fig. 395. Set the main bracket plate in position on the engine and 
bolt it securely in place, using the original paper gasket, the cap 
screws, the bolts, the nuts, and the cotter pin. Then bolt the main 
bracket plate 785 to the water-outlet header 834, using the two 
bolts (26X1), the lock washers (9X10), and the plain washers (2X48), 
Fig. 396. The commutator-brush assembly and the housing should 
now be [^replaced, taking care to put them in their original posi¬ 
tions; then connect the spark-advance rod on the commutator 
housing. 

Installing the Unit. Generator-Motor. The generator-motor 
unit should now be placed in position on the main bracket plate 
with the chain-adjusting stud 829 in place on the unit. This chain¬ 
adjusting stud should rest freely in the bottom of the slot at the top of 
the main bracket plate. Assemble on this chain-adjusting stud 829, 
the plain washer (2X44), the lock washer (9X12), and the nut 
(20X13). Place the lower adjusting bolt 868 in the slot provided for 
it on the main bracket plate. A lock washer (9X12) and a nut 
(20X13) are provided for this bolt. Place these in their respective 
positions, but do not tighten either the upper or the lower chain¬ 
adjusting bolts at this time. 

With the unit loosely in place, proceed with the chain equipment 
as follows: Place the generator-shaft spacer 856 and the Woodruff 
key (21X9) on the generator shaft. Fig. 396. Place the gear and the 
sprocket assembly 919 also on the generator shaft, so that the large 
gear is on the inside toward the main bracket plate. Place the chain 


ELECTRICAL EQUIPMENT 


563 


811 around the sprocket 776 and also around the small sprocket on 
the generator shaft, taking particular care that the open side of the 
crankshaft sprocket is toward the front of the car. With the two 
sprockets and the chain in this position, slide the crankshaft sprocket 
776 and the gear and the sprocket assembly 919 into place on the 
crankshaft and on the generator shaft, respectively, taking care that 
the starting-pin hole in both the crankshaft and the crankshaft 
sprocket 776 are in alignment. Insert the starting pin 814 with the 
counterbore of the cotter-pin holes toward the front of the car. 
These holes are also to line up with the two corresponding holes in the 
rear wall of the crankshaft sprocket 776. When the two cotter pins 
(3X7) are inserted, it is necessary that they be placed clear through 
and bent over flat against 
the rear face of the crank¬ 
shaft sprocket 776. Unless 
secured in this manner. 

Fig. 397, there is great 
danger of the cotter pins 
breaking off and allowing 
the starting pin 814 to 
come out. This ivill 
result in serious damage 
to the entire system. By 
means of the fillister-head cap screw (25X1), Fig. 396, in the upper 
chain-adjusting stud 829, raise the generator-motor unit'until the chain 
is reasonably tight. Then securely lock it in position by tightening 
the upper and the lower holding-stud nuts (20X13). The generator- 
motor unit and the driving-chain equipment are then securely 
installed. 

Chain Drive. The chain cover 832 is next to be placed in posi¬ 
tion, Fig. 396, using the cap screws (26X5) and the lock washers 
(9X9) to hold it securely to the main bracket plate. Place one of the 
fan-belt guards 841 on the generator shaft, with the three projections 
toward the front of the car. Then assemble the fan-belt pulley 828 
against this guard and complete the fan-belt pulley assembly with the 
other fan-belt guard 841, this time, however, placing the three pro¬ 
jections toward the rear of the car. These projections serve as 
centering points for the guards on the fan pulley, and the guards must 



Fig. 397. Correct Heinze-Springfield Assembly 
of Crankshaft Sprocket 


























564 


ELECTRICAL EQUIPMENT 


be assembled with the projections toward the pulley. This assembly 
should be locked securely to the generator shaft by the use of the plain 
washer (2X44) and the castellated nut (14X5). The cotter pin 
(3x7) must then be placed through the end of the shaft to lock this 
nut. Next install the motor rear-stiffening bracket 858 on the motor¬ 
brush head, using the bolt (25X4) and the washer (2X48) under the 
bolt head. Do not tighten this bolt until after drawing down 
the cylinder-head bolt securing the bracket to the engine. 

Over the old Ford fan pulley assemble the two half pulleys 784, 
using the screws 804, the lock washers (9X6), and the nuts 
(13 X12), Fig. 396. By this means, the fan belt runs closer to the fan 
blades than before. Now mount the fan in position on the main 
bracket plate 785, using the original Ford screw. Place the lock 
washer (9X12) between the Ford fan bracket and the main bracket 
plate, to lock the fan bracket securely in place. Adjust the new fan 
belt 836 over the two pulleys to the proper tension. 

Bendix Drive. Next install the Bendix drive 812 on the starting- 
motor shaft. Fig. 396. Remove the drive bolt of the Bendix unit 
and place the latter on the shaft; then replace the drive through the 
hole in the end of the shaft and secure by means of the lock washer and 
the nut, taking care to bend the small projection on the special Bendix 
lock washer upward against the side of the nut. 

Final Assembly. Before replacing the radiator, put back the 
hand crank and turn the engine over several times by hand to note 
that everything is properly installed and operates freely. Solder one 
end of each headlight ground wire to the inside face of the radiator, 
bringing the wires out through the holes provided for the headlight 
wiring, and be sure to allow sufficient wire to reach the head¬ 
light sockets. Then replace the radiator, using all the original bolts, 
nuts, gaskets, and cotter pins. It is advisable to turn the fan blades 
over slowly by hand before using the starting crank to make sure that 
the blades do not interfere with any part of the starting system or with 
the radiator. It is advisable to replace the hose connections of the 
radiator with new ones, and they must be tightened up very carefully 
to guard against leaks. When refilling the • radiator, it should be 
noted whether there is the slightest sign of a leak and, if there is, it 
should be corrected at once, as any water falling on the starting 
system will injure it. 


ELECTRICAL EQUIPMENT 


565 


Switch and Wiring. Remove both the front and the rear floor 
boards from the car. About one inch to the right of where the steer¬ 
ing post passes through the dash, there is a hole in the toe board, which 
was originally provided for the horn tube. Remove this board and 
enlarge the hole to the left about IJ inches, using this hole to bring 
the wiring through from the motor to the switch. Remove the Ford 
“magneto to coil” connection and also the “switch to terminal wire” 
connection and discard both of them. Also remove and discard all 
of the old headlight wiring. With the switch bracket in hand, see 
that the stay rod is screwed in flush with the face of the bracket. 
Next place the switch in the bracket so that the “off” position of 
the switch is on top, or nearest the switch-bracket flange. Fasten the 
switch securely to the switch bracket by means of four flat-headed 
screws. 

Take the complete wiring assembly as received, enclosed in the 
13-inch length of the circular loom, and, with the switch mounted in 
the switch bracket, connect the wires, being careful to assemble the 
proper terminals on the proper binding posts. Fig. 398, as follows: 
one large wire with the terminal SM on the post SM; one large wire 
and one small wire SB on the post SB. There then remain three small 
wires with the terminals C, M, and L, which are to be placed under 
the heads of the spring-terminal posts bearing the corresponding 
letters. The spring terminal AM is for the ammeter only. 

Assemble the switch and the bracket on the dash. By use of the 
two switch-bracket clamps, the fillister-head screws, and the lock 
washers, fasten the switch bracket to the dash, slightly to the left of 
the steering post, in such a position that the hole in the end of the 
stay rod will line up with the Ford body bolt. Remove the nut 
from this bolt and clamp the stay rod securely. The foregoing 
instructions refer to the Ford touring car, the runabout, and the coupe- 
let models. 

In the case of the sedan model, by the use of three round-head 
blued wood screws, fasten the switch bracket to the dash, slightly to 
the left of the steering post, in such a position that the hole in the end 
of the stay rod will line up with the Ford body bolt. Remove the 
nut from this bolt and clamp the stay rod securely. This is a special 
stay rod 943 and is supplied only for the sedan model, so that the 
latter must be specified in ordering. 




566 


ELECTRICAL EQUIPMENT 





1 1 


i 1 





Fig. 398. Wiring Diagram of Heinze-Springfield Ford System without Ammeter or Dash Lamp 






















































































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Fig. 399. Wiring Circuit of Heinze-Springfield Ford System without Ammeter or Dash Lamp 















































































































568 


ELECTRICAL EQUIPMENT 


Coil and Magneto Wiring. Extending through the 13-inch length 
of the circular loom are two wires, one end of each being (connected 
to the spring terminals C and M on the back of the switch, P"ig. 398. 
Connect the wire from the terminal C to the magneto terminal on the 
rear of the Ford coil box; connect the wire from the terminal M to 
the magneto contact on the flywheel housing. These two terminals 
were formerly connected by the Ford ‘‘magneto to coil wire”, which 
has been discarded. Fig. 399. 

Charging Wire and Starting Cable. On the back of the switch 
on the post SB are connected one large and one small wire. Fig. 398. 
The small wire is to be connected to the terminal on the regu¬ 
lator A. On the back of the switch on the post SM is connected 
the “switch to starting motor” cable, on the other end of which the 
terminal M is to be connected to the upper, or positive, starting- 
motor brush. 

Wiring for Lights. On the back of the switch on the spring termi¬ 
nal post L is connected a lighting cable, which is to be connected to 
the headlights and the tail light. Fig. 398. Three wires are provided 
which are to be used to ground one side of each light. To ground the 
tail light, run the ground wire under the tail-light frame bolt. If an 
oil lamp is used, tape the end of the light wire which is provided for an 
electric tail light and secure it to the tail-light bracket, so that if the 
electric light is subsequently installed, the wiring will be there for it. 
Secure the lighting cable to the car frame at several convenient points 
to keep it free from oil and to prevent chafing, which would cause 
grounding of the lighting circuit. When single-contact lamps are 
used, ground wires are not necessary, as one side of the lamp socket 
itself is grounded. 

Battery Cables. Before connecting the positive (+) battery 
terminal to the switch terminal and the negative (—) battery termi¬ 
nal to the ground cable, be sure that the switch is in the “off” position. 
Then connect these wires as follows: Under the front floor board is the 
Ford transmission-case cover which is held in place by six bolts. 
Remove the upper right-hand bolt and assemble under this the 
starting-cable clamp. From the post SB on the back of the switch. 
Fig. 398, run the positive battery to the switch cable, placing it under 
the starting-cable clamp. Pass this cable through the circular loom 
placed between the running-board apron and the bottom of the body, 


ELECTRICAL EQUIPMENT 569 

and through the hole in the battery box to the positive terminal of the 
storage battery. 

Remove the two lowest bolts on the transmission-case cover 
and clean the transmission-case cover with a piece of sandpaper or 
emery cloth to insure a good electrical contact at this point. Under 
these bolt heads, assemble the brass ground strip on one end of the 
negative of the battery to the ground cable and run the other end 
through the circular loom mentioned above, then through the hole in 
the battery box to the negative terminal of the storage battery. 
Tighten these wires securely to the storage-battery terminals, using 
pliers for this purpose. 

Installing the Battery. On all the different types of Ford cars, 
the battery is placed on the right-hand running board, midway 
between the front and the rear fenders, particular notice being taken 
that the battery box does not interfere with opening the door. In the 
bottom of the battery box are six holes, the four inside holes being 
provided for the four carriage bolts holding the battery box on the 
running board, and the two outside holes being provided for the two 
battery hold-down rods which hold the storage battery securely in 
place. Six corresponding holes t¥ inch in diameter must be drilled 
in the running board, to correspond to the six holes in the bottom of 
the battery box. Two wood pads are provided, which are to be 
placed inside the battery box. Two steel reinforcing pads are also 
provided, which are to be used under the running board. Place the 
four carriage bolts down through the wood pads, the battery box, 
the running board, and the steel pads, and clamp by means of 
carriage-bolt nuts. Next place the storage battery in the battery box 
with the positive (+) terminal toward a rear of the car, and by means 
of the hold-down rods which are hooked over the handles of the 
storage battery, fasten securely, using lock washers and nuts. 

At a point midway between the two wire holes in the battery box, 
pry down a part of the running-board apron with a large screwdriver 
or a pinch bar, providing sufficient space between the running-board 
apron and the bottom of the body for the four-inch length of the 
(circular loom through which the two battery cables pass. 

Choker, or Priming=Rod, Assembly. On the air-gate lever of 
the carburetor, connect one end of the choker cord under the outside 
bolt which connects the carburetor and the inlet pipe, assemble 


570 


ELECTRICAL EQUIPMENT 


the choker loop in a vertical position, and pass the choker cord 
through the upper loop. On the dash, to the left of the carburetor 
adjustment, drill a |-inch hole. Through this hole pass the other end 
of the choker cord and connect the choker ring. This choker assem¬ 
bly displaces the Ford choker wire (carburetor-priming device), 
which extends through the radiator before the starting system has 
been installed. It is used to shut the air supply from the carburetor, 
so as to increase the suction through the carburetor nozzle and facili¬ 
tate starting. 

Tail and Side Lights, Horn, Etc. The use of an electric tail 
lamp is not necessary to the operation of the system. Provision has 
been made for an electric tail lamp, which is not furnished with the 
equipment, but, owing to the small additional cost and its great 
convenience, its use is advised. It should be wired as shown in the 
wiring diagrams. Figs. 398 and 400. If a single-contact tail lamp is 
used, it is not necessary to employ the ground wire, as one side of the 
lamp socket is already grounded to' the car frame. In as much as 
there is emobdied in the lighting system a light-dimming resistance for 
the headlights, which is governed by the combination switch, it is not 
advisable to convert the oil side lamps to electric. ' The horn supplied 
on the Ford (No. 196 and later models) car is operated by the alternat¬ 
ing current from the magneto. This horn may be used without inter¬ 
fering with the starting system, but cannot be operated by the 
storage battery. If desired, a direct-current horn may be installed 
and should be connected as shown in Figs. 400 and 401. 

Ammeter and Dash Lamp. These are not furnished with the 
system as described, but may be had at an additional cost. This 
equipment consists of a switch bracket and an ammeter reading to 30 
amperes, charge and discharge; a single-contact dash lamp with a 
self-contained switch and all the necessary wiring. In order to con¬ 
nect the ammeter in the charging circuit, there must be a spring 
binding post on the back of the combination switch AM, Fig. 400. 
All of the later combination switches of this make are fitted with this 
binding post. On the back of the combination switch, from the spring 
binding post AM to the round-head screw, there is connected a small 
flat brass strip.' Break this strip connection by cutting in the center, 
using the pliers or a hack saw. Connect the ammeter and the dash 
lamp in the circuit, as shown, being very careful to connect the wire 


I 





ELECTRICAL EQUIPMENT 


571 



Fig. 400. Wiring Diagram of Heinze-Springfield Ford System with Ammeter and Dash Lamp 

















































































































572 


ELECTRICAL EQUIPMENT 


from the post SB to the ‘^discharge” side of the ammeter and 
the wire from the spring binding post Jf to the “charge” side of the 
ammeter. One end of the charging wire, running from the battery 
positive terminal of the regulator and the cut-out to the terminal S B 
on the back of the switch, must be changed over from the terminal 
SB to the binding post AM, Figs. 398 and 400. 

Testing and Operation. Place the brake lever, the spark, and the 
throttle levers in the usual starting position, then unlock and rotate 
the combination switch lever to any of the three positions desired, 
as follows: “lights off, ignition on”; “lights dim, ignition on”; 
“lights bright, ignition on”. Depress the starting button in the 
center of the combination switch. This sends the current from 
the storage battery through the starting motor, and the rotation of 
the starting motor causes the small gear on the Bendix shaft to mesh 
with the gear on the generator shaft. Riveted to this gear is the 
sprocket over which the silent chain runs. During the interval that 
the starting motor is in. operation, a heavy current is drawn from the 
storage battery, and, if the lights are on, there will be a perceptible 
dimming caused by the decrease in the battery voltage. This is 
especially noticeable when the battery is nearly discharged, and will 
also be more apparent when the engine is stiff and hard to crank, or 
when there is a loose connection in the battery circuit. Although a 
fully charged battery is capable of cranking the engine for several 
minutes, it is "not [advisable to continue cranking longer than a few 
seconds, owing to the heavy discharge. If the engine does not start 
in this time, the choking device should be used to prime the carbu¬ 
retor. Should this not start the engine, investigate the cause before 
cranking further, as otherwise the battery will be exhausted. Fre¬ 
quent discharging of the battery in this way shortens its life. The 
front and the rear bearings of the starting motor should be oiled every 
500 miles, though the Bendix drive-screw shaft should never be oiled 
nor lubricated in any way. The screw gear works to the best advan¬ 
tage when the shaft is dry. 

As the mounting bracket is bolted to the machined surface of 
the timing-gear housing of the engine, the silent chain must be 
kept in good alignment at all times, and it must also be kept suffi¬ 
ciently tight to prevent it from striking the chain guard as well as to 
avoid the possibility of the chain teeth riding the sprocket, in which 



Fig. 401. Wiring Circuits of Heinze-Springfield Ford System with Ammeter and Dash Lamp 





























































































































574 


ELECTRICAL EQUIPMENT 


case the chain will break because of the severe strain placed upon it. 
The battery cut-out is designed to close when the car is traveling 
about 6 miles per hour, at which speed the charging current is 
about 4 amperes, increasing rapidly to 10 to 12 amperes at 10 miles 
per hour. After the car has been run the first hundred miles with the 
starting system in operation, the chain should be adjusted to take up 
the slack caused by the stretch; after that it should be inspected about 
every 300 miles. The operation of the regulator and the care of the 
system is given in detail in connection with the general descriptions, 
in alphabetical order. 

FISHER 

Preparing Engine. This is a twelve-volt two-unit type, the two 
members of which, for convenience in mounting, are combined as a 



Fig. 402. Crankshaft Pin and Sprocket on Fisher Ford Installation 


single mechanical unit. To install, the radiator, the water connec¬ 
tions, the fan, the starting crank, and the fan pulley on the crankshaft 
must be removed. The lower water connection, or elbow, at the side 
of the cylinder block need not be taken off, but must be loosened. 
Place the new sprocket 102FB5A, Fig. 402, on the end of the crank¬ 
shaft, driving the pin H through the cross-hole in the end of the 
crankshaft, burring the pin slightly so that it cannot drop out. This 
secures the sprocket to the engine crankshaft. The pin F is placed 
in the sprocket before shipment. 

Then slip the pulley 102FB7A over the end of the sprocket up to 
the shoulder. Secure the pulley by several center punch marks 
between the end of the sprocket and the internal diameter of the 
pulley at D. If it is desired to retain the Ford starting crank in place 

































































ELECTRICAL EQUIPMENT 


575 


(this is preferable to carrying it in the tool box), cut A inch oflf the 
crank ratchet C, Fig. 402, at the shoulder B —the original hole in 
the crank ratchet C and the starting crank are not disturbed. If 
there are burrs on the crank ratchet or if it is too large to enter the 
chain sprocket, the tips must be filed off or turned down in a lathe. 

Mounting the Starting Unit. Remove the right-hand bolt of the 
top water connection 102FBI6, Fig. 403, and the second bolt on top 
of the cylinder 102FB12. If there are rough places on the casting 
under these bolts, they must be removed. Take from the starting 
unit bracket 102FB3 and place the bracket in the position shown in 
Fig. 403. Between the bracket 102FB3 and the water connection 
is placed a heavy steel spacing washer. The bracket must be bolted 
securely in place against the water connection by the bolt 102FB12. 
The careful placing of the bracket and the clamping of these bolts is 
essential to the successful operation of the installation. After the 
bolts mentioned are securely in place, turn the set screw 102FB10 until 
it rests securely and firmly on the engine casting and, when it is firmly 
bedded, lock it securely by screwing home the lock nut. The purpose 
of this set screw is to take care of the stresses between the shaft of 
the generator and the crankshaft of the engine; note that the end of the 
screw must rest on the casting, otherwise the driving chain may be 
injured. 

Place the starting unit 102S1A on the bracket and clamp it in its 
lowest position with the nuts on the studs. A long-shank T-wrench 
is the handiest to use for this work. The chain, which is coupled with 
a bolt and a cotter pin, may now be put in position. Roll the chain 
under the sprocket I02FB5B and on the sprocket 102FB13 on the 
electric unit. Bring the links together and slip the bolt through 
toward the radiator and put the washer and the cotter pin in place. 
Tighten the chain by loosening the nuts. Fig. 403, holding the 
starter to the bracket and the nuts 102FB18, then turning the set 
screws 102FB11 up until the chain feels taut when pressed with the 
fingers. Tighten the bracket nuts and the lock nuts 102FB18. Turn 
the engine over a few times with the starter and tighten the chain 
again. This should be repeated after the car has been in use a few 
days. The life and the service of the chain will be greatly increased 
by keeping the proper tension on it, particularly during the first few 
days it is in use, when it is stretching. 


570 


ELECTRICAL EQUIPMENT 



t 



i Fig. 403. Front and Side Elevators of Fisher Ford Starter 























































































































ELECTRICAL EQUIPMENT 


577 


Separate the split pulley 102FB9, Fig. 404, and the clamp on 
the shaft of the fan between the brass pulley and the fan blades by 
the two screws. The diameter of the bore of this pulley is slightly less 
than that of the neck of the fan so that it may be filed down with a 
round file to fit the neck of the fan pulley. When this pulley is in 
position, hook the round belt 1()2FB8A, Fig. 403, furnished with the 
equipment, over the pulley on the crankshaft and the pulley 
on the fan. 

Remove the plug from the top of the electric unit and, with the 
aid of a grease gun, squirt one-half pint of good transmission grease 
into the gear case of the unit, and then replace the plug. This will 
lubricate the gears for a period of six months. 



Battery and Wiring. The battery box may be located on either 
running board as convenience dictates, holes being drilled in the 
apron to pass the battery cables. Place short pieces of |-inch 
“flexduct”, or circular loom, in the wiring holes through the battery 
box and the metal apron of the car and the 1-inch flexduct between 
the transmission cover and the engine hanger on the left and let it 
extend back past the brake pedals. Place the instrument board 
carrying the ammeter, the lighting switch, the starting switch, 
and the dash lamp, under the cowl dash to the left of the steering 
column. The length of the wires necessary to connect the battery 
to the various essentials can now be measured to suit this particular 
installation. 

Run the large negative starter cable from the negative ( —) post 
of the battery through the flexduct insulation in the battery box and 
by the transmission case to the negative post on the motor. From 



































578 


ELECTRICAL EQUIPMENT 


the positive terminal of the battery, run a cable through the flexduct 
insulation to the binding post of the starting switch, as shown in 

Fig. 405; from the other 
binding post run a cable 
to the positive brush 
holder of the motor. 
The terminals on these 
cables should be sol¬ 
dered, and the binding 
posts tightened with a 
wrench. (Whenever sol¬ 
dering has to be done 
on electric wires, use a 
noncorrosive flux and 
not an acid, as the latter 
not only is an electrical 
conductor but will also 
corrode the joint sur¬ 
faces.) 

Run the lighting 
cable from the lower 
brush G on the starting 
unit and connect to the 
terminal G on the relay. 
Connect another light¬ 
ing cable from the post 
S on the generator to 
the post 8 on the relay. 
Run a lighting cable 
from the lighting switch 
to the side lamps, as 
shown, grounding one 
side on some metal part 
of the chassis. Take 
the wire running to the 
headlights from the 
original push-button switch on the car and connect it to the proper 
binding post on the new lighting switch. Connect the lighting cable 



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ELECTRICAL EQUIPMENT 


579 


from one side of the dash lamp to the tail lamp, grounding one side of 
the tail lamp, as shown. When the wiring is finished as above outlined, 
test each circuit, making certain that all the connections have been 
made in accordance with the wiring diagram, Fig. 405. Solder and tape 
all the joints, and tighten all the terminals with a wrench. Close the 
ignition switch, press the starter button, and the engine should be 
turned over by the starting unit. As soon as the engine begins to run 
at a fair speed, the ammeter should indicate a charge going into the 
battery. Then stop the engine and turn on the lights; the ammeter 
should then show a discharge reading. 

Operating Instructions. As is the case with the majority of 
Ford starting systems, the choker wire to the carburetor is taken from 
the front of the radiator and carried up through the dash. In cold 
weather it is always advisable to pull this wire and flood the car¬ 
buretor when starting. Driving the starter with a loose chain is 
dangerous and should be avoided, so that the tension of the chain 
should be inspected at regular intervals until it has seen sufficient 
service to have stopped stretching. The starter—that is, the gener¬ 
ator—must not be run with the battery disconnected unless the small 
wire S is removed from the binding post on the generator. No 
attempt should ever be made to start with the spark lever advanced. 
Instructions for the care of the brushes and the commutator, the loca¬ 
tion of short-circuits, grounds, and the like, will be found to be the 
same as those outlined in connection with the description of other 
Ford systems. 

NORTH EAST 

Preparing Engine. While a single unit of the chain-driven type, 
this differs from the others of this type already described only in the 
details of the chain drive. Remove.the radiator and the water con¬ 
nections, the fan, the fan bracket, the screw for adjusting the 
fan, the fan pulley on the crankshaft, the starting crank, the timer 
rod for the advancing and the retarding ignition timing, one bolt 
holding the gear-case cover to make place for the stud 2394, and five 
bolts on the lower flange of engine base to make place for the bolts 2369, 
Fig. 406. Before removing the timer rod, carefully mark the timer 
housing and place a corresponding mark on the timing-gear case in 
order that the ignition timing of the motor may not be altered when the 
new timer rod, provided with the North East equipment, is installed. 


580 


ELECTRICAL EQUIPMENT 


Mounting Starter. The numbers for the various parts given in 
the following instructions for installing the unit, all refer to the illus¬ 
tration, Fig. 406. Place 
the chain sprocket 2374 
on the crankshaft and 
fasten with the pin orig¬ 
inally used for holding 
the Ford fan pulley; re¬ 
place a split cotter pin in 
each end of the large pin 
[ for locking purposes, as 
in the original mount¬ 
ing. Then replace the 
starting crank. Screw 
the stud 2388 in place 
and lock it by passing a 
split cotter pin through 
the hole at the inner 
end. Be sure that the 
shoulder of this stud 
is brought up tight 
against the finished face 
on the timing-gear hous¬ 
ing (casting), so that 
the stud will be in abso¬ 
lute alignment with the 
crankshaft. 

Screw the stud 2394 
in place and lock it with 
a cotter pin. If the boss 
of the timing-gear hous¬ 
ing at this point is rough, 
it should be smoothed 
down with a file before 
screwing home the stud. 
Fasten the hinge bracket 2396 by five bolts 2369, inserting them from 
below, and lock the nuts used on these bolts by split cotter pins; then 
assemble the cradle 2395 with the generator-motor unit in the hinge 



‘(,-■{1! 'W" 
- 














































































ELECTRICAL EQUIPMENT/ 


581 


bracket, being sure to place the split cotter pins at each end of the 
hinge pin 2399 for locking purposes. 

If necessary to clear the sprocket bracket, chip off a slight amount 
of the vertical rib on the gear cover of the engine directly over the 
crankshaft bearing. Mount the assembled sprocket bracket 2379 on 
the studs 2388 and 2394. Be sure that one washer 2478 is placed 
on the stud 2388 before mounting the bracket; pay strict attention to 
see that there is no clearance between the shoulder of the stud and 
the bracket. If necessary, place filler washers on this stud so that 
no strain will be placed on the bracket when the nut on the clamp stud 
2394 is securely fastened. It is very necessary that the chain sprockets 
be in absolute alignment. Be sure to use a straightedge to make certain 
that the sprockets line up accurately. This is very important. To 
take care of any longitudinal variation; filler washers are supplied for 
placing on the mounting studs between the sprocket bracket and the 
shoulders of the studs. These filler washers should be used if neces¬ 
sary to bring the sprockets into proper alignment. After the sprockets 
have been accurately lined up, mount the timer rod 2475. 

Mount the horizontal chain by threading downward over the large 
sprocket on the countershaft (upper shaft), then around the motor- 
generator sprocket, and make the connection by inserting the master 
link from the rear. Then mount and connect the vertical chain 
in a similar manner. INIake sure that the connecting links are 
properly locked after the loose side plates are in place. Adjust the 
vertical chain to a moderate tension by relieving the nut on the clamp 
stud 2394 and screwing down the adjusting screw 601, Fig. 406. 
After adjustment has been made, be sure to lock the adjusting screw 
by means of the jam nut and screw down the nut on the clamp stud 
which has been previously relieved. 

To adjust the horizontal chain, release the clasp nut 626 and turn 
the generator toward the engine. This will take up the slack in the 
chain. Cut off* the fan pulley with a hack saw so that the hub on 
the fan will be f inch long, as shown in Fig. 406. Make certain that 
the one fiber] washer 3138 is first placed on the shaft, then the fan, 
then another fiber washer 3138, then the two steel washers 3130 with 
the spring 3140 between them. Pressure should be applied to com¬ 
press the spring until the cotter pin 646 can be dropped through the 
hole in the end of the shaft. This is important, as it forms a friction 


582 


ELECTRICAL EQUIPMENT 



Fig. 407. Wiring Diagram for Complete North East Ford Installation 



































































ELECTRICAL EQUIPMENT 


583 


clutch strong enough to drive the fan and at the same time provides 
for a certain amount of relief to the sprockets, the chain, and the fan. 

Turn the engine over by hand to inspect the working of the chain. 
iMake careful examination to be sure that all the bolts and all the nuts 
are in place and properly fastened. Oil both the chains with a liberal 
amount of semi-liquid graphite grease. 

Mounting Battery. Install the battery on the runabout, as 
shown in Fig. 407; on touring cars the battery should be mounted 
under the rear seat, as far forward as possible. To mount the battery, 
cut holes through the floor board of the car, large enough to clear the 
battery. Lay the board 3141, Fig. 408, on the upper face of the lower 
flange of the frame panels and bolt firmly by using steel clamping 
strips 3142 placed on the underside of the channel frame. Now 
fasten the battery in place by means of the hook bolts 2460, being sure 



that the flat washers and the lock washers are placed between the 
board and the nuts on the bolts. If the muffler interferes, it is well 
to cut a groove in the board to clear it and to place a piece of asbestos 
sheeting between the board and the muffler. 

When the car is not already equipped with electric lamps, it will 
be necessary to install new lights or to mount reflectors in the head¬ 
lights and adapters, or sockets, in the side and the rear lamps. 
JMount the lighting switch and run wires to all the lamps and to the 
battery location, but do not connect the wires to the battery as yet. 
Also run the wires to the motor-generator. Figs. 407, 408, and 409. 
Special care should be taken that all the wires are made fast to 
the wood body and that the insulation on the wires is doubly pro¬ 
tected by tape or circular loom where the wires pass through the sheet 
metal. For fastening the wires, use leather cleats and insulated 
staples as supplied. 






























584 


ELECTRICAL EQUIPMENT 


Replace the radiator, taking care not to omit the gaskets and the 
leather radiator seats, and, at the same time, mount the starting 
switch 2367, Fig. 406, by the bolts holding the flange of the return- 
water tube to the engine. After completing this, fill the radiator. 
Also mount the guide bracket 2368 for the starting button 2366, as 
shown in Fig. 409. Connect the switch wires to the motor generator, 
as shown in Figs. 406 and 407. Replace the floor boards, after 
notching them so as to clear the conduit running from the lighting 
switch downward. Carefully connect the battery wires to the two 
wires coming from the general circuit. Connect one lead at a time 
and carefully wrap the connector with tape before making another 
connection. Be sure to use plenty^of insulating tape over these connec¬ 
tions so that they will be well protected. After the connections 

have been made and insu¬ 
lated, see that the leads are 
properly fastened. If the 
wires have to be made longer 
to accommodate the coupe 
or the other special bodies, 
care should be taken to see 
that the extensions are made 
of the same size and type of 
wire that is used in the re¬ 
mainder of the system. Tight 
mechanical joints, well sol¬ 
dered and taped, should be made. The use of any smaller wire will 
preyent the proper operation of the system. Where possible to avoid 
it, the distance between the battery and the electrical unit should 
never be increased. 

Operating Instructions. After the car has been run a few hun¬ 
dred miles, inspect the driving chains and, if necessary, adjust to take 
up any slack. This should be done at intervals until all stretch has 
been taken out of the chain. Inspect the chains carefully from time 
to time to see that nothing has disturbed their alignment. The chains 
should be kept clean by washing with gasoline every few weeks and 
applying a new supply of graphite grease to their inside faces. To 
adjust the vertical chain, release the nut on the clamp stud 2394 and 
screw down the adjusting screw 601, Fig. 406. Be sure to lock this 



Fig. 409. Details of Dash Wiring for 
North East System 















ELECTRICAL EQUIPMENT 


585 


screw with the jam nut after adjusting. If after adjusting the vertical 
chain the horizontal chain requires further adjustment, loosen the 
clamp holding the generator unit and turn the latter in a counter¬ 
clockwise direction until the proper tension of the chain is secured, 
then re-tighten the clasp. 

Inspect the wiring from time to time to make certain that none 
of the connections are loosening up, and when washing the car, see 
that no water is allowed to fall on the generator or on the wiring. 
See that the cover on the rear end of the generator is always tight in 
its place. This cover is detachable for the purpose of inspecting the 
brushes and the commutator. If necessary to remove the generator 
at any time, see that the terminals of all the loose wires are well 
wrapped with electric insulating tape. This is important, since if 
these wires should come in contact with each other or with the metal 
parts of the car, a short-circuit may occur and ruin the battery. In 
disconnecting the wires, be sure to tag them properly so that they can 
be replaced correctly, as improper connections may damage the sys¬ 
tem. The battery alone will supply the current for the lamps when 
the generator is removed from the car, but if used for any length of 
time with the generator off, the battery will naturally run down 
and have to be recharged from an outside source; care should be 
taken not to permit the battery to discharge too low before doing 
this. 

If it should be necessary to run the generator with the battery 
disconnected from the system, remove the small 10-ampere fnse 1183, 
Fig. 406, located over the brushes inside the detachable hood at the rear 
end of the generator, but be sure to replace this fuse when the battery is 
again connected. If at any time the generator is not charging the 
battery properly, although the system tests out in good condition 
throughout, it is evident that the fuse 1183 has been blown and should 
be replaced by a new one of the same capacity. The purpose of this 
fuse is to protect the generator from injury. The bearings of 
the generator, when assembled by the manufacturer, are packed 
with a special lubricating compound, so that no provision is made 
for oiling them. 

The lamps required are 14-volt 18-c.p. G-16i bayonet-base bulbs 
for the headlights, and 14-volt 4-c.p. G-8 bulbs with the same type of 
base for the side and rear lights. 


586 ELECTRICAL EQUIPMENT 


SPLITDORF 

Preparing Engine. Disconnect all water and gasoline connec¬ 
tions and the radiator brace rod, which should be pushed back 
through the dash out of the way, and remove the radiator. If the 
machine is fitted with electric lights, disconnect the wiring. Fig. 410. 
Remove the fan and its connections and then turn the engine over by 
hand until the pin holding the fan pulley on the crankshaft is perpen¬ 
dicular. This brings the pin over the hole in the engine base in 
position to be driven through it. Drive out the pin holding the dog 
clutch of the starting crank and pull out the crank. Fig. 411. Drive 



Fig. 410. Dismounting Radiator Lamps 

Courtesy of Splitdorf Electric Company, 
Newark, New Jersey 


Fig. 411. Removing Hand Crank and Fan 

Courtesy of Splitdorf Electric Company, 
Newark, New Jersey 


out the pin holding the fan pulley to the crankshaft, and a smart blow 
on the pulley itself will free it from the shaft. In case the pin is rusted 
in place, a little kerosene will help to free it. 

Remove bolts B and C, Fig. 412, then loosen the nut A, but before 
removing it from the bolt tie a piece of twine around the bolt to pre¬ 
vent it from falling into the engine base or the crankcase. In case 
it should drop, it will remain in the hole, and a sharp tap directly 
beneath it on the crankcase will cause it to jump upward, when it can 
be caught with the fingers. Place the adjustable bracket in position 
and secure it to the engine, using new bolts supplied at B and C with 
the nuts formerly on the old bolts. The bolts and nuts holding the 













ELECTRICAL EQUIPMENT 


587 


lower part of the bracket must be carefully tightened, as it is impor¬ 
tant that this part be held firmly. 

Mounting Starter. Place the split taper sleeve on the engine 
shaft, using a fine file if necessary to smooth off any burrs. Drive a 
pin through the sleeve and the shaft until it is flush with the sleeve on 
both sides. With the key in position, place the sprocket on the sleeve, 
registering the keyway with the key. A nut is then turned on to 
draw the sprocket up on the taper sleeve, and it also causes the sleeve 
to grip the crankshaft securely. 



Fig. 412. Placing Adjustable Bracket in Position 
Courtesy of Splitdorf Electric Company, Newark, New Jersey 

Replace the starting crank, start the chain under the sprocket in 
mesh, and with the aid of the crank turn the engine over slowly until 
the chain is drawn through for about half of its length, making certain 
that the chain is working freely. Fig. 413. Then fasten the generator- 
motor unit to the adjustable bracket with the three bolts and lock 
washers furnished. This can be accomplished easily by tilting the 
bracket. Pass the chain over the generator sprocket, joining the 
chain with the pin and locking the pin with a washer and cotter pin. 
Align the crankshaft and generator-motor sprocket by means of the 
adjustable bracket hinge bolt. Adjust the chain to its proper tension, 
i.e., without any slack. The chain should never be allowed to run in 











588 


ELECTRICAL EQUIPMENT 


a slack condition, as it may break. x\djusting screws on the bracket 
provide an easy means of keeping it at the right tension. 

The fan pulley furnished with the outfit is an aluminum die¬ 
casting in two parts and is designed to clamp over the Ford fan pulley. 
It is held on by four screws and lock washers and brings the center in 
line for the fan belt. Fill the recess of the fan with grease and replace 
the fan, using the original bearing stud; place the belt on the fan 
pulley and on the generator-motor pulley and adjust to proper ten¬ 
sion. Like the chain, this pulley should be so tight that there is no 
undue slack, but tightening it too much should be guarded against. 



Fig. 413. Adjubting Driving Chain 
Courtesy of Splitdorf Electric Company, Newark, New Jersey 

as this only places an excessive strain on the shafts and does not make 
the fan run any better. 

Wiring. The details of the various holes to be drilled or cut and 
the wiring to be installed are given in Figs. 414 to 419. Prepare the 
dash for the wiring, as shown in Figs. 415 and 416, which give the 
location and sizes of all holes— A, Fig. 416, for the ignition switch, B 
for the lighting and dimming switch, and C for the wires leading to the 
indicating automatic switch (battery cut-out with indicator to show 
whether the battery is charging or not). Unless a magneto is used for 
ignition, A may be omitted. 

Bore*a |-inch hole in the permanent floor board, as shown in 
Fig. 414, following the dimensions there given for its location. Install 













ELECTRICAL EQUIPMENT 


589 


the starting switch with the front of the switch lengthwise with and 
facing the right-hand side of the car, Fig. 419, and at the same time 



Fig. 414. Details of Wiring for Splitdorf Ford Installation 


-Lighting SwitchB 



Fig. 415. Details of Wiring on Dash 


tlie light-dimming switch should be placed in position with the coil 
end of the switch facing down. AW wire terminals are marked to 





























































































































590 


ELECTRICAL EQUIPMENT 


correspond with similar marks on all parts of the installation. Lay 
wiring assembly in the sill of the car, as shown in Fig. 419, connecting 
the wires to the front of the dash, as in Fig. 415. (Reference to Fig. 



Fig. 416. Layout of Drilling on Dash for Ford Installation 


418 will facilitate the installation.) Connect wires to indicating 
automatic switch in accordance with diagram on the back of the 
switch, after which fasten the switch to the steering column about 3| 
inches from the dash. Connect wires, as marked, to corresponding 



Fig. 417. Method of Running Cables from Batteries 
on Splitdorf Installation 


terminals on the generator-motor and likewise to the starting switch. 
Prepare the curved running-board guard, or apron, for the battery 
leads and the running board for securing the battery box in accord¬ 
ance with the instructions given on Fig. 414. Place the battery box 











































































ELECTRICAL EQUIPMENT 


591 


on the running board, resting it on the two wood cleats and fasten it 
down with the bolts, nuts, and lock washers furnished. 

Place the battery in the box with the outside terminals toward 
the car. Pass the extension cables under the wood sill of the car 
body and over the channel steel frame of the car, connecting the 
extension leads from the battery to the starting switch, as marked. 
I he method of passing the cables around the sill and frame are shown 
in Fig. 418. After connecting the cables to the battery, cover all the 



terminals and exposed parts of wires with vaseline or grease to prevent 
corrosion. 

Wiring Diagram. In the wiring diagram. Fig. 418, double wiring 
is used throughout, so that there are no ground connections. When 
the engine is running so that the unit is operating as a generator, the 
current flows from terminal +Z) on the generator to a similarly 
marked terminal on the indicating switch, through the voltage coil of 
the battery cut-out, and thence to the terminal +/1 on the switch, 
where it divides, one side leading to + A on the battery and through 
the battery to —A on the starting switch. The other half of the 
current flows through a jumper in the switch to +jB on the starting 
switch, through to the same terminal on the battery, and through 
the battery to —B on the starting switch. It will be noted that 






































































592 


ELECTRICAL EQUIPMENT 


the common return points of the current at the starting switch are 
— B and — ZI,and from there the current flows to — Don the generator. 



Fig. 419. Plan of Ford Chassis, Showing Installation of 
Splitdorf Starting Switch 


Starting Switch. When the starting switch is closed by depress¬ 
ing its foot button, the current flows from -\-A at the battery to +.1 



























































































































































































































































































ELECTRICAL EQUIPMENT 


.593 


on the starting switch, through the switch to -\-M on the switch, and 
thence to the terminal -\-M on the motor, through the latter to —B 

— Z) on the starting switch, and then to — R on the battery, through 
the battery to the -\-B terminal, and thence to the -\-B terminal on 
the starting switch, through the switch to —A on the switch, and 
thence to the — A terminal on the battery, and through the battery 
to +^,completing the circuit. 

Instructions. Generator-Motor. See that the unit is lined up 
accurately so that the chain runs perfectly true. If this is not done, 
the chain will be noisy and will wear abnormally on one side and even¬ 
tually break. A poorly aligned chain will also wear the sprockets. 
Match the chain carefully during the first hundred miles or so of 
running and, as often as required, take up any slack that appears 
until the chain seats itself. The life of the chain will be greatly 
prolonged by keeping it well lubricated and at the proper tension. 

If for any reason it becomes necessary to remove the battery from 
the car, the engine must not be run without first connecting terminals 

— D and -f Z) of the dynamo with a piece of copper wire. 

The commutator should be kept clean by wiping at regular 
intervals with a clean rag; if it becomes blackened, note whether there 
is undue sparking between the brushes and the commutator and, if 
necessary, sand-in the brushes to correct this. LNe No. 00 sandpaper 
for this and also for brightening up the face of the commutator itself. 
After this operation, remove all traces of carbon, sand, and metallic 
dust from the commutator housing as well as from the spaces between 
the commutator segments. Do not change the position of the brushes 
or alter the tension of the brush springs unless they have weakened 
after one or more years of running. See that the brush leads do not 
rub against the armature, as this will chafe the insulation off and 
cause a ground or a short-circuit. The generator-motor should be 
oiled about every thousand miles, using five to six drops of good light 
oil in each oil hole. See that the fan belt is running true on the pul¬ 
leys, otherwise it will ride the flange of the pulley and either fly off 
or break. 

Startmg Switch. If the brushes of the switch wear unduly, see 
that the foot button of the switch is not sticking in the floor board. ' 
The hole through which the rod of the button operates should be 
large enough to prevent the pedal spring from rubbing against the 


594 


ELECTRICAL EQUIPMENT 


floor board. The switch sticking down will cause both its own 
brushes and those of the generator-motor to burn and wear badly. 
See that when the starting-switch pedal returns to its normal position 
proper contact is made. This can be determined by removing the 
cover of the switch. 

Indicaimg Automatic Switch. When the engine is running very 
slowly, the dial may indicate ON and OFF in rapid succession, 
fluttering continually. This is caused by the engine running at, or 
very close to, the speed at which the battery cut-out is designed to 
operate, so that no attention need be paid to it. Should this fluttering 
occur at medium or at high speeds, it indicates a loose connection in 
the wiring, either on the generator line, on the back of the cut-out, 
or in the starting switch. This, if neglected, will cause the contact 
points of the battery cut-out to burn badly, so that all connections 
should be gone over regularly to see that they are kept tight. As the 
generator output is controlled by means of a reversed compound field 
winding, or bucking coil, there is no regulating device combined with 
the battery cut-out. The battery has six cells, all of which are con¬ 
nected in series for starting, giving current at 12 volts. For both 
charging and lighting, the cells are coupled in two units of three each 
in series-multiple, so that 7-volt lamps are used. They are protected 
by a fuse on the back of the battery cut-out. 

WESTINQHOUSE 

Preparing Engine. Adjust the ignition and the carburetor so 
that the engine fires evenly and regularly before beginning the instal¬ 
lation. Remove the radiator and water connections, three forward 
left-cylinder head bolts, and the fan and bracket timer. Turn the 
engine shaft until the pin in the fan pulley is in a perpendicular 
position h, and then remove the starting crank and the fan pulley. 
Fig. 420. Use a bulldozing tool to expand the front end of the engine 
oil pan. Figs. 421 and 422. (This tool is obtainable from the West- 
inghouse Company.) It is very important that at least |-inch clear¬ 
ance beyond the sprocket be obtained, as shown in Fig. 433. Be sure 
to use the bulldozing tool with the spacing hub XI, Figs. 421 and 
422, always next to the engine case. The tool is made in two parts 
and is reversible so as to be available for right-hand and left-hand 
operations. 



ELECTRICAL EQUIPMENT 


695 


Mounting Starter. The crankshaft sprocket II is assembled by 
the manufacturer and adjusted to the correct tension. Dismantle the 



Fig. 420. Ford Engine Ready for Installation of 
Westinghouse Electric Equipment 


sprocket. See that the pin hole in the crankshaft is in a vertical 
position h, Fig. 420, and then drive the new sprocket hub II, Fig. 423,' 
in place so that the hole in the sprocket is in line with the hole in the 




Fig. 421. Use of Bulldozing Tool on 
Westinghouse Ford System 


Fig. 422. Using Hammer to Help 
Bulldozing Tool 


crankshaft. The sprocket hub must be a tight fit on the crankshaft 
and should be driven into place by means of copper or brass bar, as 



















500 


ELECTRICAL EQUIPMENT 


shown at h, Fig. 423. Drive the pin II-l, Fig. 424, through the 
sprocket hub II and the shaft, and be sure that the head end is flush 
with the surface of the hub. If the pin II-l is not a tight fit in the 



Fig. 423. Putting on Crankshaft Sprocket Hub in 
Westinghouse System 


shaft, it should be bent slightly at the center to make it tight. Use a 
drift for driving pin II-l into place so as not to injure the pin or the 



H 


Fig. 424. Inserting Sprocket Pin with Drift 

hub. To be sure that the pin II-l in not projecting too far at the 
extended end, place the sprocket II-4, Fig. 425, on the hub and turn 
it several revolutions. If it does not turn freely, the pin 77-/, 
















ELECTRICAL EQUIPMENT 


597 


Fig. 424, probably strikes the inside of the sprocket, and therefore 
the pin should be trimmed until it just clears. 

Remove the sprocket 11-4 place one of the friction collars 
II-5 on the hub. Now spring the spring ring II-2, Fig. 425, into place 
on the hub II, so that the small 
hole in the ring engages with the 
projecting end of the small pin. It 
will not go into place any other 
way. Be sure that the free end of 
the spring ring projects at least 
inch out from the surface of the 
sprocket hub, Fig. 425. Place the 
chain I under the sprocket hub. 

Slide the sprocket 11-4 over the 
spring ring. Pack the sprocket 
with good cup grease and place the 
other friction washer 11-5 on the 
forward side of the sprocket. Now 
place the stationary washer 11-6 over the keyway in the sprocket hub 
and put the spring washer 11-7 on the outside of this and fasten it in 
place with the nut 11-8, as shown in Fig. 425. The nut 11-8 should 
be tightened until the mark “O” on the nut corresponds with the 
mark in the keyway a on the hub. Fig. 42G. The grooves in the face 

of the nut should register with the flukes of the 
spring washer. 

Remove the nut from the forward left-hand 
bearing bolt and replace it with a special flat 
Westinghouse nut G-1, as shown in Fig. 420. 
Place the lock washer G-2 on top of this nut 
and screw the cylindrical nut G down tight with 
the lock washer. Replace the Ford timer. Set 
the Westinghouse electric [unit A, Fig. 427, in 
place on the engine, using in the cylinder head 
the three special screws D (furnished for this pur¬ 
pose) and the special cylindrical nut G (provided). Adjust the 
center distance between the engine crankshaft and the electric-unit 
shaft, as shown in Fig. 427. The distance should be 1 If| inches, 
as shown, and all three points of support shonld touch. 



Fig. 426. Detail of 
Sprocket Showing 
Adjustment 



Fig. 425. Assembly of Westinghouse 
Crankshaft Sprocket 







Fig. 428. Putting on Shaft Sprocket and Chain 

less than 10 pounds, adjust the center distance as directed until the 
required tension is obtained. A new silent chain is elastic to some 


.508 ELECTRICAL EQUIPMENT 


Remove the sprocket B from the electric unit shaft, Fig. 428. 
Insert the sprocket in the endless driving chain / and press the 




Fig. 427. Adjusting Distance between Centers of 
Crankshaft and Motor Shaft 


sprocket on the shaft, as shown. When the sprocket is in place, there 
should be at least 10 pounds tension on the chain. If the tension is 




























ELECTRICAL EQUIPMENT 


599 


extent, and, for this reason, a new chain is adjusted to run under the 
tension mentioned. After running about 2000 miles, the chain may 
be loose enough to strike the chain guard. This is a warning to tighten 



the chain. To do this, loosen the three bolts. Fig. 429, 'about one 
full turn from the top supporting bracket. Tighten the adjusting 
bushings nearest the radiator until the tension is correct. Set the 
other bushings to agree and tighten all the support bolts. Do not nm 



Fig. 430. Tightening Mounting Bracket with 
Shaft Pulley in Plates 

Courtesy of \Vestinghouse Electric and Manufacturing Company, 
East Pittsburgh, Pennsylvania 


the chain under tension after the first adjustment. This is very impor¬ 
tant. If the chain is too tight, it will produce a grinding noise. When 
})roperly adjusted, the chain should be so loose that when pressed on 
with the finger it will give about J inch. 




















600 


ELECTRICAL EQUIPMENT 


After replacing the fan pulley B-1 and tightening the nut B-2, be 
sure to replace the cotter pin B-3, Fig. 430. Mount the chain guard 


Fig. 431. View of Westinghouse Installation, Showing Chain Guard 
and Part of Wiring Arrangement 


¥ 


( 






-jl 

V 



Fig. 432. Fan in Place and Headlights Mounted 

L on the unit and see that it lines up, as shown in Fig. 431. Clamp 
the split fan pulley J on the Ford fan pulley, as shown in Figs. 428 
and 430, and replace the fan on the engine, using the new fan belt Ah 




















ELECTRICAL EQUIPMENT 601 



Fig. 433. End and Side Elevations of Westinghouse Ford Installation, Showing Correct Position of Parts on Engine 





































































































































































002 


ELECTRICAL EQUIPMENT 


Fig. 432. Bend the fan blade sligntly to clear the electric unit. 
Instead of the Ford cranking claw and pin, use the Westinghouse 
sleeve II-9 and pin II-IO, respectively, Fig. 433. When the Ford 
starting crank is replaced, it may be found slightly out of alignment. 

Insert a bar in the starting- 
crank bearing and spring the 
bearing into alignment. This 
completes the installation of 
the unit itself. 

Lighting and Starting 
Switches. Mount the two- 
gang lighting switch P on the 
right-hand side of the dash. 
Cut a rectangular hole in the 
dash at a point low enough so 
that the carburetor adjusting rod will not touch the contact screws of 
the switch when it is fastened in place by means of four wood screws 
to the cover plate on the face of the dash. Mount the fuse Q just 
below the lamp switch on the engine side of the dash, as shown in 

Fig. 431. Note that on 1915 Ford cars 
the new cowl dash may make it necessary . 
to change the location of the speedometer 
slightly in order to provide space for the 
lamp switch. 

The starting switch and generator 
cut-out 0, Fig. 434, should be located on 
the heel board at the left-hand side of 
the car, approximately 2 inches from the 
car frame. The terminals should be 
toward the right side of the car. Mount 
the battery box on the right running 
board, as shown in Fig. 435, and drill two 
Fig. 435. Method of Mounting J-iiicli lioles in the mild shield to match 

Battery Box on Right Running i i i • i 

Board in Westinghouse the lioles 111 the battery box, Fig. 436, and 

System ^ ^ ^ ^ , 

fasten down with the holding-down bolts. 

Wiring. The wiring should now be fastened in place, as shown 
in Figs. 437 and 438. If Westinghouse lamps are used, the dimmer 
should be removed. Except where wood screws may be used to 








Fig. 434. Diagram Showing Mounting of Starting 
Switch and Cut-Out 




































ELECTRICAL EQUIPMENT 


603 


attach holding cleats to wood parts, all the holding eleats should be 
fastened under the bolts already on the Ford chassis. Be very careful 

that the cable terminals do not 
touch any jmrt other than the studs 
to u'hich they should he fastened. 
Carelessness in this particular 
will result in burned-out appa¬ 
ratus and may actually ruin the 
battery before the car is ever run. 
It is equally essential to prevent 
the metal armor on the cables 
from touching any of the con¬ 
necting studs or the terminals. 
The '"ground wire should be fas¬ 
tened at one end under one of the 
supporting bolts of the starting 
switch and cut-out and at the 
other end by fastening the con¬ 
nection together with a cleat 
under the bolt holding the brake 
and clutch rod to the frame. Do 
not connect the ground wire from 
the battery until all the other wires 
are in place and fastened. The 
ground connection of W is made 
by fastening the connection 
under a bolt of the muffler sup¬ 
port 

Attach the lamp connections 
to the wires. These are of the 
solderless type which are con¬ 
nected by removing the con¬ 
nector from the lamp, Fig. 439. 
Slip the casing a back over the 
cable and push the wires through 
the collar b. Strip the insulation 
from the wire about J inch back from the end. With a small screw¬ 
driver applied to the sleeve d, remove the little metal socket c from 










































































TiTsggiriiaranwriaasi^^ 


;gmxsssg, 


Si^U 


f ( 


MOTOR AND 
GENERATOR 




AimSSSmita 


LAMP SWITCH 


GROUND WIRE 


tiSCiMSSiiEHM 


R AND S 
STORAGE BATTERY 


y* II 

§ 


I uf 

1 


W-6 



Fig. 437. Pictorial Wiring Diagram of Westinghouse Ford System with 
Other than Westinghouse Ford Lamps 


awifgar* 

































































W-6 


R AND S 
STORAGE BATTERY 


W-7 


- riiaii 


MOTOR AND 
GENERATOR 


MP SWITCH 


r 

W-5 


Fig. 438. Pictorial Wiring Diagram for Westinghouse Installation when 
Westinghouse Ford Lamps Are Used 








































































60G 


ELECTRICAL EQUIPMENT 


the connector. Insert the })are ends of the wire in the socket and 
fasten with small set screws. Replace the socket and fasten it by 
screwing up on the sleeve d. Be sure that none of the strands of the 
wire project outside of the insulation piece e. Attach the head and 
tail lamps, insert the connecting plugs, and try all circuits to deter¬ 
mine if everything is operating satisfactorily. 

When Westinghouse Ford electric head lamps are used. Fig. 438, 
connect them as shown in the diagram, grounding one wire from each 
lamp, also one wire from the tail-light socket. One switch button 
will give a dim light and the other switch will give a bright light. 
If other than the above lamps are used, such as the double-bidb two- 

wire type headlights, one wire from each lamp socket 
must be grounded to the lamp housing or the car 
frame, and the dimmer should be disconnected. If 
side lights are used instead of double-bulb headlights, 
with two-wire (double contact) lamps, both wires 
in cables TF-7 and TF-^ can be used for the head¬ 
lights, as shown in the diagram for the Westing- 
house Ford lamps. The dash end of one wire in 
each cable must be grounded instead of connecting 
it to the switch. An additional wire from the switch 
should be run to one terminal in each side light, and 
Fig. 439 Details of the otlier lamp terminal should be grounded. The 

Westinghouse Lamp 

Connector dimmer should then be disconnected. 

If side lights are used instead of double-bulb headlights with 
single-wire lamps, both ends of one wire in the cables W-7 and W-8 are 
useless and should be taped up. An additional wire from the switch 
should be run to eaeh side light. 

Westinghouse Ignition. Assembly. If the Westinghouse igni¬ 
tion system is also to be installed, it should be assembled in place at 
this time, i.e., before replacing the Ford timer housing, the radiator, 
and other parts, which have been removed to install the electric 
starting and lighting unit. Remove the timer, or spark advance, rod; 
the steel bush; the Ford roller contact; the coil box; and all igni¬ 
tion wiring. Place the Westinghouse gear Z-1, Fig. 432, on the cam¬ 
shaft in place of the Ford timer roller contact, and fasten it in place 
with the same pin, cap, and nut used to hold the roller contact. Take 
out the spark plug of the first cylinder. Turn the engine over until 





ELECTRICAL EQUIPMENT 


607 


the piston of cylinder No. 1 is exactly at the upper dead center on the 
firing stroke, that is, when the piston is at the top of the cylinder icith 
both mhes closed. The position of the valves and the piston may be 
seen through the spark-plug hole. ]\Ioimt the ignition unit in the 



Fig. 440. First Step in 
Installing Westing- 
house Ignition 


Fig. 441. View of Ignition 
Installation, Showing 
Timing Position 


supporting bracket and put the holding screw in place. Be sure that 
the ignition unit turns freely in the bracket. Remove the distributor 
block and slide the ring cover up. Turn the entire unit until it is in 
the position shown in Fig. 441. Hold the unit firmly in this position 



Fig. 442. Arrangement of Westinghouse Ignition Wiring 

and turn the distributor brush arm counter-clockwise (to the left) 
until the contact brush is in the position shown in Fig. 441 and the 
interrupter contacts are just beginning to open. Clamp the unit in 
place on the engine exactly in this position. Use the two special 
screws Z-4 to hold the bracket in place on the engine. 

















G08 


ELECTRICAL EQUIPMENT 


Connect the timer rod Z-5, furnished with the equipment, to the 
ignition unit, as shown in Fig. 442. Operate the spark lever on the 
steering post and see that the Westinghouse ignition unit follows the 
movement of the control lever. iVIount the cover plate on the dash 
over the holes left by the Ford coil unit and cut a rectangular hole in 
the dash to receive the Westinghouse ignition switch. Fasten the 
cover plate and the ignition switch to the dash with the screws 
furnished for the purpose. Put the distributor block in place on the 
ignition unit and connect the wires to the spark plugs, as shown in 
Fig. 442. Be sure to connect each plug to the point shown in the 
diagram. Connect one end of the small wire Z-7 to the terminal at the 
side and near the bottom of the ignition unit that has no other connec¬ 
tion and connect the otherj end to the terminal on the ignition switch. 

There are terminals provided for the purpose of reversing the 
current through the interrupter contacts; changing the short connec¬ 
tion from one side to the other side and changing the primary wire 
reverses the current direction. Connect the terminal B on the switch 
to the negative side of the battery. This connection can be made most 
easily by using the terminal B-1 on the starting switch, as shown in 
Figs. 437 and 438. The positive side of the battery is grounded. 
The engine may now be started in the usual way. 

Operating Instructions. The Westinghouse-Ford system is a 
12-volt single-unit single-wire type, the complete unit being per¬ 
manently connected to the enginge by the silent-chain drive. The 
driving sprocket has a cushioned positive drive in the starting direc¬ 
tion and a friction drive in the generating direction. This friction is 
adjustable for wear without removing any part of the equipment, as 
described later under Failure of Generator. 

A battery cut-out, or magnetic switch, in the generator circuit 
serves to protect the battery; it cuts in when the engine attains a 
speed approximately equivalent to nine miles an hour on the direct 
drive. On low, it will naturally operate at a very much lower car 
speed as the engine is then running very much faster. If no lights 
are on, the battery begins to charge as soon as the cut-out operates; 
with lights burning, part of the current is diverted to them, but, at 
fifteen miles an hour or over, sufficient current is furnished to light 
all the lamps and charge the battery. The details of the cut-out, also 
of the starting switch, are shown in Fig. 443, while the method of 


ELECTRICAL EQUIPMENT 


G09 


reassembling the carburetor choker, strangler, or priming device, as 
it is variously termed, with the new equipment provided, is shown in 
Fig. 444. In case the engine fails to start after the starting motor 
has operated five to ten seconds, the ring on the dash should be pulled 
as far as it will go and held there for a few seconds while the starting 
motor is operated again. Do not hold the ring down too long; if the 





Fig. 443. Con.struction of Westinghouse Starting Switch and Cut-Out 


engine does not start promptly with the carburetor choked, the fail¬ 
ure must be caused by something else, and continuous running with 
the carburetor air inlet closed will quickly flood the engine with 
liquid gasoline. 

Starting Troubles. If the electric motor fails to start when the 
switch is closed, open the switch and test out as follows, using a direct- 
current voltmeter: Connect voltmeter to give a reading of over 12 









































































































610 


ELECTRICAL EQUIPMENT 


volts and test the battery. If the reading with the lamps on is 11 
volts or less, the battery is practically exhausted. Instructions for 
keeping the battery in good condition will be found under its appro¬ 
priate heading in the section on Storage Batteries. Trouble of this 
nature, particularly in cold weather, is frequently caused by not driv¬ 
ing the car long enough between stops, so that the generator has no 
opportunity to charge the battery. Look for an open circuit, i.e., 
broken wire or loose terminal, in the wires JV, W-1, and W-2, Figs. 
437 and 438. Remove the spring collar over the brushes and see 
that they are in good condition, not sticky or gummed with oil and 
dirt, and are making good contact over their entire bearing surface on 
the commutator. 

To Remove Brushes. Lift the spring that holds the brush in the 
guide and take out the screw holding the brush shunt, when the brush 

can be slipped out. In re¬ 
moving each brush, it should 
be noted which side was turned 
up, and each brush should 
be replaced in its original 
holder in the same way. In 
putting in new brushes, care 
should be taken to see that 
they have a good bearing fit 
over their entire surface on 
the commutator. To obtain this, they must be sanded-in (see 
Delco instructions). Only brushes supplied by the manufacturers of 
the system should ever be employed. 

Battery Does Not Stay Charged. If the car is not run for a 
sufficient length of time during the day or at a speed high enough to 
charge the battery, there may a ground in the wiring. With the 
engine idle and the lights off, disconnect the battery wire and touch 
it lightly on the terminal a few times. If a spark occurs, there is a 
ground in the wiring. The battery may not charge even at high 
speeds, owing to different causes. If there is a loose connection between 
the starting switch and the electric unit, see that the terminals hold 
the wire W-2 tight and examine the wire between the terminals for 
breaks. The cut-out may not be operating properly. With the 
engine running, vary the speed and watch the contacts of the cut-out 




















ELECTRICAL EQUIPMENT 


611 


to see that they connect the battery in the circuit at a speed above 
nine miles an hour and break the circuit again when the speed drops 
below this point. The cut-out contacts should be separated when 
the engine is not running, and they should remain closed as long as 
the engine runs above a certain speed. This cutting-in speed varies 
slightly. If the contacts do not close, there may be oil oh the brushes 
or on the commutator; or one of the brushes may be worn too short; 
or one of the brush springs may be too loose. 

Loose Friction Drive. If the commutator, the brushes, all the 
connections, and the wiring are in good condition, the trouble may be 
caused by the generator drive. To find out whether the friction 
sprocket has lost its tension or not, try to turn the electric unit by 
hand in both directions with the engine stationary. If it can be 
turned by hand easily in one direction, the nut II-8 should be tight¬ 
ened sufficiently to enable the engine to drive the electric unit. Fig. 
425. When running at 15 to 20 miles an hour, a faint click may be 
heard about every five minutes. If the clicking is more rapid than 
three or four times every five minutes, tighten the adjusting nut one- 
third to one-half turn. 

The shunt-field brush a may not touch the commutator, Figs. 
437 and 438. Adjust this brush, sanding it in, if necessary, and if this 
does not correct the ’trouble, test out the shunt-field circuit for open 
connections. This includes all circuits through the starting switch 
and the shunt-field winding. If the shunt-field winding is found to 
be open-circuited, the trouble was, no doubt, caused by an open 
circuit between the generator and the battery or by running the 
generator disconnected from the battery. 

Lamps Do Not Light. If confined to a single lamp, this may be 
owing to the bulb having burned out, to an open circuit, or to a broken 
connection in the wiring. Should replacing with a new bulb not 
correct the trouble, test all the connections and the wiring and see 
that the lamp socket is grounded. When none of the lamps will light, 
test for a voltmeter reading with the lamps turned on but with the 
engine idle. If the voltmeter shows no reading, this may be owing 
to a broken connection at the battery or to the terminals having 
become so corroded as to amount to the same thing. The wire W may 
be disconnected or broken. If the voltmeter reading is correct, the 
trouble may be caused by a blown fuse. Should this be the case, do 


ELECTRICAL EQUIPMENT 


012 

not replace it immediately, but look over the wiring and the con¬ 
nections for an accidental ground or a short-circuit. In looking for 
grounds, hunt for abrasions of the insulation on the wire or for 
mechanical contacts between the ends of the cables or current- 
carrying parts of the wiring devices and the metal of the car, the socket, 
the shells, etc. When the trouble has been located and corrected, 
replace the blown fuse with another of the same type and capacity. 
If the trouble cannot be located immediately, turn off the switch on 
the damaged circuit and do not use until it can be remedied. Should 
the trouble be in a particular lamp socket, disconnect the attachment 
plug from this socket until the difficulty can be remedied and see that 
the removed attachment does not dangle against the metal of the 
car in such a way as to cause short-circuits. 

All the lamps may be burned out. This is likely to happen when a 
battery wire breaks or becomes disconnected. It is also not unlikely 
that the battery may be entirely exhausted, though it will seldom get 
down to a point where the lamp filaments will not glow at least a 
dull red, without its condition having been detected. If the lamps 
become dim as soon as the engine stops, this indicates an exhausted 
battery, and if not convenient to drive the car to recharge it, the 
battery should be charged from an outside source. When the lamps 
flicker or go out momentarily, there is a loose.connection, and the 
fact that all the lamps are thus affected indicates its location at the 
battery or in the wire JV-1, Fig. 437. Should but one lamp be affected, 
only its particular circuit is at fault, and the trouble will usually be 
found in the socket itself, though a parted ground connection, which, 
owing to the vibration, will sometimes touch and at other times be 
shaken away from its contact, may be responsible. As a 6-cell 
battery is supplied, 14-volt lamps must be used. 

Operatio7i of Ignition Unit. The vertical ignition unit of the 
Westinghouse type is composed of four essential units, viz, the inter¬ 
rupter, or contact-breaker; the induction coil; the distributor; and the 
condenser. The operation of the interrupter may be observed by 
lessening the thumb screw E and sliding upward the loose section of 
the insulating housing which forms the interrupter cover. Fig. 445. 
With the ignition switch “On” and the engine running, each segment 
of the interrupter cam, in turn, passes on and off the fiber bumper. 
Fig. 445. As each cam passes off the bumper, the interrupter contacts 



ELECTRICAL EQUIPMENT 


013 


close, closing the circuit from the battery to the primary winding 
of the coil. Then, as they are lifted by the bumper, the contacts are 
separated, suddenly opening the circuit and inducing a high-tension 
current in the secondary of the induction coil. This current is directed 
by the distributor on top of the ignition unit to the proper spark 
plug. The ignition switch is a simple^ single-pole type connecting 



CAM 


PLATE 


INDUCTION COIL 


DISTRIBUTOR 
RM 


CONTACTS 


ADJUSTING 

SCREW 


Fig. 445. Parts of Westinghouse Ignition Unit 


the negative side of the battery to the ignition terminal. Fig. 44G. 
This switch is a reversing type, i.e., it changes the direction in which 
the current passes through the interrupter contacts each time it is 
operated. Particular attention is directed to the rear view of the 
switch. As received, this switch does not operate to reverse the 
current direction. If it be desired to utilize this feature, remove the 



Fig. 446. Front and Back Views of Westinghouse Ignition Switch 


metal strip that connects two of the three terminals on the ignition 
unit. Also remove the metal strip that connects two of the four 
switch terminals. Connect the terminal on the switch to the center 
terminal on the ignition unit. Obtain two extra wires, like the one 
supplied to connect the switch and the ignition unit, and connect the 
two switch terminals to the two outside terminals on the ignition unit. 














614 


ELECTRICAL EQUIPMENT 


Ballast Resistor. This is a resistance unit which will be noted 
mounted on the rear face of the switch, Fig. 446. It is connected in 
series with the primary ignition circuit and is an important part of 
the ignition system, its function being to protect both the ignition 
system and the battery. In case this resistance unit should become 
broken or inoperative from any cause, a standard 5-ampere fuse may 
be used in an emergency, but a fuse of more than 5-ampere capacity 
must never he employed in any case. Unless absolutely necessary to do 
so in order to run the car, the ignition system should never be oper¬ 
ated without the ballast resistor, as serious injury is likely to result. 
A very fine piece of wire, such as a single strand of lamp cord, should 
be used for bridging the gap. 

ELECTRIC QEAR=SHIFT 

General Plan. One of the more recent additions to the electrical 
equipment of the automobile that the installation of a generator and 
a constantly charged storage battery on the car has made possible is 
the electric gear-shift. While it has not yet been extensively adopted, 
it is already in use on a number of cars and is slowly coming into 
favor, and from now on the garage man will find more machines thus 
fitted coming into his hands and will be called upon to give attention 
to this as well as to the other parts of their electrical equiprnent. 

In the standard three-speed and reverse gear of the selective type, 
four movements are necessary to engage all the speeds. These 
changes in the relations of the gears are carried out by means of a 
sliding pinion for first and second speeds, a toothed clutch for direct 
drive, and the interposition of an idler between two of the driving 
gears to give the reverse, all these movements being accomplished by 
means of a yoke on the member to be moved. This yoke is mounted 
on a movable rod, or bar, which is, in turn, connected through con¬ 
venient linkage to the hand lever. In the electrically operated gear, 
all these parts, with the exception of the hand lever, which is dis¬ 
pensed with, remain the same and their functions are unaltered. The 
bars on which the yokes are mounted, two in number. Fig. 447, are 
lengthened somewhat, and their extended ends form armatures, or 
cores, for four solenoids. 

Principle of Action. As has been explained in the introductory 
in connection with electromagnetism, passing a current through a 



ELECTRICAL EQUIPMENT 


615 


Push-Bullons Hre 


solenoid will cause it to draw its core into the coil. This is the prin¬ 
ciple on which the electric gear-shift operates. There is a solenoid 
for each movement necessary. For example, to obtain first speed, 
the bar yl, which carries the yoke attached to the sliding gear (not 
shown), must be moved to the left. Fig. 447. To accomplish this, 
button 1 is pressed. This closes the circuit through the solenoid 1, but 
no current flows through its winding until the master switch control¬ 
ling the current supply to all the solenoids is closed. The master 
switch is operated by pushing the clutch pedal forward, exactly as 
when shifting a gear by hand. This energizes solenoid 1, the bar A 
moves to the left, carrying the sliding pinion with it by means of the 
usual yoke, and the first- 
speed gear is engaged. The 
operation throughout is the 
same. A neutralizing device, 
described later, opens the 
master switch and cuts off 
the current. The speed de¬ 
sired is selected by pushing 
the numbered button under 
the steering wheel, the clutch 
is disengaged momentarily by 
pushing the pedal all the way 
forward when the change is 
•desired, and the gears shift 
automatically. Thus the solenoid 2 moves the bar A to the i ight to give 
second, or intermediate, speed; solenoid 3 moves the bar B to the left 
to give the direct drive, or high speed; while R moves the same bar to 
the left to give the reverse engagement. 

The buttons on the steering post, when pressed do not entirely 
close the circuit but merely place the particular solenoid which they 
control in connection with the master switch. They are known as 
“selector switches”. They select in advance the circuit which will be 
energized when the master switch is closed. To do this, the clutch 
pedal must be depressed all the way, in order to permit de-clutching 
without bringing this switch into action, that is, when the clutch pedal 
is depressed only part way, as in cutting off the power, no contact is 
made at the master switch. 



Bear 5?iifling Mechanism i3_ Mounted on Top of 
Transmission Case 


Fig. 447. 


Diagram Showing Principle of 
Electric Gear-Shift 


Courtesy of Cutler-Hammer Manufacturing 
Company, Milwaukee, Wisconsin 










































616 


ELECTRICAL EQUIPMENT 


Stopping the Car. When it is desired to stop the car, the clutch 
pedal is depressed all the way, after the neutral button has been 
pressed. Pressing this button breaks any contacts that may have 
been made previously by the selector switch buttons, and depress¬ 
ing the clutch pedal then brings into action what is termed the 
neutralizing device. For example, the car has been running on high, 
the neutral button is pressed and the clutch pedal pushed all the way 
forward. This causes the operating lever K to move ahead. Fig. 
448. Then the neutralizing cams F pull on the boss on the shifter 
forks as if a shift were to be made, and the master switch M will also 
close; but, as the neutral button has opened all the selector switches. 



Fig. 448. End View of C-H Neutralizing Mechanism ] 
and Master Switch 

Courtesy of Cuttler-Hammer^ Manufacturing 
Company, Milwaukee, Wisconsin 

no current flows, and as the solenoids are not energized, the gears 
remain in neutral. Fig. 449 shows a plan view of the neutralizing 
mechanism and the master switch, while Fig. 450 illustrates the 
solenoids (two of them) and their mounting in detail. The relative 
locations of these solenoids to the remainder of the operating mech¬ 
anism is shown by the phantom view of the complete gear box. 
Fig. 451. The solenoids are identified by the letters Bl, 2, etc., and 
their cores by,the letters Cl, 2, etc. A complete wiring diagram is 
given in Fig. 452. 

Starting First Speed. Assuming that the gears are in neutral 
and it is desired to start, then first-speed button of the selector switch 
on the steering wheel is pressed, partly closing the circuit of one of 






ELECTRICAL EQUIPMENT 


617 


the magnets. Depressing the cluteh pedal all the way rotates the 
lever K through the connecting rod L which is linked to the clutch 



Fig. 449. Plan View of C-H Neutralizing IMechanism and Master Switch 
Courtesy of Cutler-Hammer Manufacturing Company, Milwaukee, Wisconsin 
J 

pedal. This pulls the blades of the master switch M into contact, conU 
pleting the circuit and energizing the solenoid. *As the gears engage, 



Fig. 450. View of Magnet Case and Electric Solenoids 
Courtesy of Cutler-Hammer Manufacturing Company, Milwaukee, Wisconsin 


and the sliding member is within J inch of being ‘‘home”, the pawl 
G, Fig. 448, falls back, owing to the pull of the magnet agahistjthe 










618 


ELECTRICAL EQUIPMENT 


neutralizing cams F, causing it to strike against the trigger N, vv’hich 
is attached to the switch-operating pawl L. This action causes the 
pawl L to be raised out of engagement with the stem of the master 



switch, and the latter snaps open instantly, owing to the pull of the 
spring 0, Fig. 449. The actual time of engagement, during which 
current is being drawn from the battery, is said to be less than one- 
third of a second. 


Fig. 451. Phantom View of C-H Gear-Shifting Arrangement 
Courtef^u of Cutler-Hammer Manufacturing Company, Milwaukee, Wisconsin 






















ELECTRICAL EQUIPMENT 


619 


From First to Intermediate or High. Being in first speed and 
desiring to shift, the button corresponding to the speed desired, i.e., 
either intermediate or high, is pressed at the convenience of the 
driver. When it is desired to make the change, the clutch pedal is 
pushed all the way forward, this action rotating the operating lever 



Fig. 452. Complete Wiring Diagram for C-H 
Electric Gear-Sliift 


K and its shaft which carries the rocker arm 1 and its attached 
mechanism. As the first gear, or whichever gear has been previously 
operated, is still in mesh, the latch H is in engagement with the pawl 
G of the neutralizing mechanism, and, as the operating lever and the 
rocker arm I are rotated, the latch H presses against the pawl G, 
causing both of the neutralizing cams F to rotate toward the center, 












































































































G20 


ELECTRICAL EQUIPMENT 


owing to their being engaged through the teeth P. On the central 
side of the shifter forks D, Fig. 451, there is a boss, and as the neutral¬ 
izing cams F rotate, they press against the boss on whichever side is 
in engagement. This mechanically pulls the shifter fork and the gear 
with which it is engaged back to the neutral position before the next 
shift can be made. As the gear reaches the neutral position, the end 
of the latch II strikes the knockout pin. This action releases the 
latch from engagement with the pawl G, and as the operating lever K 
is moved ahead by the driver’s foot on the clutch pedal, the switch 
operating pawl L pulls against the switch stem, closing the circuit at 
the master switch. This action is the same for all speeds in the gear 
box. In case of failure of the current through exhaustion of the bat¬ 
tery or other cause, an emergency hand lever may be inserted in the 
socket S and the gears may be changed in the usual manner by hand. 

Wiring. Referring to the wiring diagram. Fig. 452, it will be 
noted that the wiring is very simple. To permit the removal of the 
gear box, if necessary, without having to disconnect any permanently 
fastened cables, all the wires are led to a terminal block, the actual 
location of which is shown on the gear box. Fig. 451. Connections 
at this terminal block are simplified by making each terminal a differ¬ 
ent size so that the wires can be replaced only on the terminals which 
correspond to them. There is, accordingly, no risk of confusing them. 
A single wire leads from each magnet coil through the terminal block 
to its particular speed button on the selector switch, while the other 
lead from the coil is connected to a neutral wire directly through the 
terminal block and the master switch to the battery. Another wire 
from the battery passes through the terminal block to the contact of 
the selector switch which is common to all speeds. The circuit is 
accordingly from the positive terminal of the battery through the 
depressed push button on the selector switch, through the winding 
of the coil to which the button in question corresponds, and back 
through the master switch to the other terminal of the battery. 

Operating Troubles. A failure on the part of the gear box to 
shift electrically would be likely to occur, after considerable usage, 
in about the following order: 

(I) A break in the linkage connecting L with the clutch pedal, 
which would prevent the neutralizing mechanism from coming into 
operation, and would also prevent the master switch from closing. 


ELECTRICAL EQUIPMENT 


G21 


(2) Dirt or wear which would prevent the fingers of the master 
switch from making proper contact; failure of the spring 0, of the 
master switch, through breakage, so that the master switch would 
not open automatically immediately upon completing the shifting of 
the gears, as is normally the case. 

(3) PNcessive jolting and vibration causing some of the leads to 
shake loose from the terminal block. 

(4) Breakage or loosening of some of the connections at the 
selector switch owing to the same cause. (The wiring itself is so well 
protected that any injury to it is remote.) 

(5) Jamming of the solenoid cores in the brass tubes in which 
they slide in the coils, owing to the shaft getting out of alignment. 
To operate properly, it should be easy to move the entire shifting 
mechanism by hand with very little effort. 

(0) Exhausted storage battery which, as a matter of fact, should 
always be tested first, but which, like the empty gasoline tank, is 
such patent cause of failure that it seems almost unnecessary to 
mention it, either first or last. As is pointed out at considerable 
length under the appropriate heading, there are numerous causes for 
the exhaustion of the battery, so that its condition should always 
be inspected before attempting to investigate the shifting mechanism. 

Should an examination prove the battery to be sufficiently 
charged, the electric test-lamp set—described in connection with 
trouble hunting in the starting and lighting systems—will prove a 
valuable aid in running down the open circuit or the short-circuit 
that is preventing the gear box from operating. Test the circuit 
of each solenoid in turn; inspect the connections of the master switch 
and the condition of its contact fingers, also the connections at the 
terminal block and at the selector switch. The test lamp should 
quickly reveal just which circuit is at fault. 



WESTINGHOUSE STARTING AND LIGHTING SYSTEM AS DESIGNED FOR H.A.L. TWELVES 

Courtesy of Westinghouse Electric and Manufacturing Company, East Pittsburgh, Pennsylvania 





























ELECTRICAL EQUIPMENT FOR 

GASOLINE CARS 

PART VHT 


ELECTRIC STARTING AND LIGHTING 
SY STEMS —(Continued) 


STARTING AND LIGHTING STORAGE BATTERIES 

Importance of the Battery in Starting and Lighting. In the 

last analysis, every electric lighting and starting system on the 
automobile is necessarily a battery system. An electric starter 
is, first and last, a battery starter, since no system can be any more 
powerful than its source of energy. In other words, the storage 
battery is the business end of every electrical starting and lighting 
system. Just as the most elaborate and reliable ignition apparatus 
is of doubtful value with poor spark plugs, so the finest generators, 
motors, and auxiliaries become useless if the battery is not in proper 
working order. 

Storage Battery Requires Careful Attention. A little experience 
in the maintenance of electric starting and lighting systems will 
demonstrate very forcibly that the relative importance of the storage 
battery is totally disproportionate to that of all the remaining 
elements of the system put together. The latter essentials have 
been perfected to a point where they will operate efficiently without 
attention for long periods. The battery, on the other hand, requires 
a certain amount of attention at regular and comparatively short 
intervals. Usually, this attention is not forthcoming, or it may be 
applied at irregular intervals and with but scant knowledge of the 
underlying reasons that make it necessary. Consequently, the battery 
suffers. It is abused more than any other single part of the entire 
system and, not being so constituted that it can withstand the effects 
of this abuse and still operate efficiently, it suffers correspondingly. 
Then the entire system is condemned. 




G24 


ELECTRICAL EQUIPMENT 


Other things being equal, the suecessful operation of any starting 
and lighting system centers almost wholly in the proper maintenance of 
the storage battery. Not all the defections that this part of the elec¬ 
trical equipment of the car suffers are caused by the battery, but unless 
properly cared for, it will be responsible for such a large proportion 
that the shortcomings of the rest of the system will be entirely for¬ 
gotten. To make it even stronger, it may well be said that unless 
the storage battery is kept in good condition, the rest of the system 
will not have an opportunity to run long enough to suffer from wear. 
In a great many cases that come to the repair man’s attention, the 
battery is ruined in the first six months’ service, usually through 
neglect. For this reason, considerable attention is devoted to the 
battery and its care in this connection, despite the fact that it is 
very fully covered in the volume on Electric Vehicles. The condi¬ 
tions of operation, however, are totally unlike in the two cases. 
In one instance, the energy of the battery is called for only at a rate 
of discharge which is moderate by comparison with the ampere-hour 
capacity, while the battery itself is constantly under the care of a 
skilled attendant. In the other instance, the demand for current is 
not alone excessive but wholly disproportionate to the total capacity 
of the battery when it is used for starting, ’and intelligent care is 
usually conspicuous by its absence. 

PRINCIPLES AND CONSTRUCTION 

Function of Storage Battery. In the sense in which it is commonly 
understood, a battery does not actually store a charge of electricity. 
The process is entirely one of chemical action and reaction. A battery 
is divided into units termed cells. Each cell is complete in itself 
and is uniform with every other cell in the battery, and one of the 
chief objeets of the care outlined subsequently is to maintain this 
uniformity. Eaeh cell consists of certain elements which, when a 
current of electricity of a given value is sent through them in one 
direction for a certain length of time, will produce a current of 
electricity in the opposite direction if the terminals of the battery 
are connected to a motor, lamps, or other resistance. The cell will, 
of course, also produce a current if its terminals are simply brought 
together without any outside resistance. This, however, would 
represent a dead shori-circmt and would permit the batterv to dis- 





ELECTRICAL EQUIPMENT 


625 


chaige itself so rapidly as to ruin its elements. This is one of the 
things that must be carefully guarded against. When attending 
a batteiy, see that its terminals are not left exposed where tools may 
accidentally drop on them. When the current is being sent into the 
battery, as mentioned above, it is said to be charging; when it is 
connected to an outside resistance, it is discharging. 

Parts of Cell. Elements. These are known as the positive 
and negative plates and correspond to the positive and negative 
electrodes of a primary battery. They consist of a foundation com¬ 
posed of a casting of metallic 
lead in the form of a grid, the 
outer edges and the connecting 
lug being of solid lead, while 
the remainder of the grid is like 
two sections of lattice work so 
placed that the openings do not 
correspond. Every manufacturer 
has different patterns of grids, 
but this description will apply 
equally well to all of them. Fig. 

453 illustrates the grid of the 
Philadelphia battery. The ob¬ 
ject in giving them this form is 
to make the active material of 
the plates most accessible to 
the electrolyte, or solution, of 
the battery, and at the same time to insure retaining this active 
material between the sides of the grid. 

This active material consists of peroxide of lead (red lead) in 
the positive plate and litharge, or spongy metallic lead, in the nega¬ 
tive plate. The plates are said to be pasted, to distinguish them 
from the old-style plates which were “formed” by a number of charges 
and discharges. The active material is forced into the interstices 
of the grid under heavy pressure, so that when completed the 
plate is as hard and smooth as a piece of planed oak plank. The 
positive plate may be distinguished by its reddivsh color, while the 
negative is a dark gray. Each positive plate faces a negative in 
the cell, and as the capacity of the cell is determined by the area 



. 


Fig. 453. Lead Grid Ready for Active XIaterial 

Courtesy of Philadelphia Storage Battery 
Company, Philadelphia, Pennsylvania 









020 


ELECTRICAL EQUIPMENT 


of the positive plates, there is always one more negative plate than 
positive plates in a cell. The lead connectors of each of the plates 
is burned to its neighbor of the same kind, thus forming the positive 
and negative groups which constitute the elements of the cell. 

Separators. As the elements must not be allowed to come in 
contact with each other in the cell because to do so would cause an 
internal short-circuit to which reference is made later, and as the 
maximum capacity must be obtained in the minimum space, the 
plates are placed very close together with wood and perforated 
hard rubber separators between them. These are designed to fit 
very snugly, so that the combined group of positive and negative 
plates is a very compact unit. When reassembling a cell, it is impor¬ 
tant that these separators be properly cared for in accordance with 
the directions given later. 

Electrolyte. To complete the cell, the grouped elements with 
their separators are immersed in a jar holding the electrolyte. This 
is a solution consisting of water and sulphuric acid in certain pro¬ 
portions, both the acid and the water being chemically pure to a 
certain standard. This is the grade of acid sold by manufacturers as 
battery acid and in drug stores as C.P. (chemically pure), while 
the water should be either distilled, be cleanly caught rain water, 
or melted artificial ice. In this connection, the expression “chemi¬ 
cally pure” acid is sometimes erroneously used simply to indicate 
acid of full strength, i. e., undiluted, as used in the cells in the form 
of electrolyte. It will be apparent that whether at its original 
strength or diluted with distilled water, it is still chemically pure. 
In mixing electrolyte, a glass, porcelain, or earthenware vessel 
must be used and the acid must always he poured mto the ivater. Never 
attempt to pour the water into the acid, but always add the acid, 
a little at a time, to the water. The addition of the acid to the water 
does not make simply a mechanical mixture of the two but creates a 
solution in the formation of which a considerable amount of heat is 
liberated. Consequently, if the acid be poured into the water too 
fast, the containing vessel may be broken by the heat. For the same 
reason, if the water be poured into the acid, the chemical reaction 
will be very violent, and the acid itself will be spattered about. 
Sulphuric acid is highly corrosive; it will cause painful burns whenever 
it comes in contact (even in dilute solution) with the skin and will 




ELECTRICAL EQUIPMENT 


027 


quickly destroy any fabric or metal on which it falls. It will also 
attack wood, for which reason nothing but glass, earthenware, or 
hard rubber containers should be employed. 

Specific Gravity. The weight of a liquid as compared with 
distilled water is known as its specific gravity. Distilled water at 
60° F. is 1, or unity. Liquids heavier than distilled water have a 
specific gravity greater than unity; lighter liquids, such as gasoline, 
have a specific gravity less than that of distilled water. Concentrated 
sulphuric acid (battery acid, as received from the manufacturer) 
is a heavy oily liquid having a specific gravity of about 1.835. A 
battery will not operate properly on acid of full strength, and it is 
therefore diluted with sufficient water to bring it down to 1.275. 
This, however, is the specific gravity of the electrolyte only when the 
battery is fully charged. The specific gravity of the electrolyte 
affords the most certain indication of the condition of the battery 
at any time, and its importance in this connection is outlined at 
considerable length under the head of Hydrometer Tests. The 
following table shows the parts of water by volume, the parts of 
water by weight, and the percentage of acid to water to produce 
electrolyte of different specific gravities. 

Action of Cell on Charge. When the elements described are 
immersed in a jar of electrolyte of the proper specific gravity, and 
terminals are provided for connecting to the outside circuit, the 
cell is complete. As the lead-plate storage battery produces current 
at a potential of but two volts per cell, however, a single cell is 
rarely used. The lowest number of cells in practical use is the 
three-cell unit of the 6-volt battery used for starting and lighting 
on the automobile. The different cells of the battery are usually 
permanently connected together by heavy lead straps, while detach¬ 
able terminals are provided for connecting the battery to an outside 
circuit. When the charging current is sent through the cell, the 
action is as follows: The original storage-battery cell of Plante 
consisted simply of two plates of lead; when the current was sent 
through such a cell on charge, peroxide of lead was deposited on the 
positive plate and spongy metallic lead on the negative. This was 
termed ‘"forming” the plate. By modern methods of manufacture, 
this active material is formed into a paste with dilute sulphuric acid, 
and is pressed into the grids. On being charged, this acid is forced 


628 


ELECTRICAL EQUIPMENT 


out of the plates into the electrolyte, thus raising the specific gravity 
of the electrolyte. When practically all of this acid has been trans¬ 
ferred from the active material of the plates to the solution, or 
electrolyte, the cell is said to be fully charged and should then show 
a specific gravity reading of 1.275 to 1.300. The foregoing refers of 
course to the initial charge. After the cell has once been discharged, 
the active material of both groups of plates has been converted into 
lead sulphate. The action on charge then consists of driving the 
acid out of the plates and at the same time reconverting the lead 
sulphate into peroxide of lead in the positive plates and into spongy 
metallic lead in the negative plates. 

Action of Cell on Discharge. The action of the cell on discharge 
consists of a reversal of the process just described. The acid which 
has been forced out of the plates into the electrolyte by the charging 
current again combines with the active material of the plates, 
when the cell is connected for discharge to produce a current. When 
the sulphuric acid in the electrolyte combines with the lead of the 
active material, a new compound, lead sulphate, is formed at both 
plates. This lead sulphate is formed in the same way that sulphuric 
acid, dropped on the copper-wire terminals, forms copper sulphate, 
or dropped on the iron work of the car, forms iron sulphate. In cases 
of this kind, it will always be noted that the amount of sulphate 
formed is all out of proportion to the quantity of metal eaten away. 

In the same manner, when the sulphuric acid of the electrolyte com- 4 
bines with the lead in the plates to form lead sulphate, the volume 
is such as to completely fill the pores of the active material when 
the cell is entirely discharged. This makes it difficult for the charging 
current to reach all parts of the active material and accounts for the 
manufacturers’ instructions, never to discharge the battery below a 
certain point. 

As the discharge progresses, the electrolyte becomes weaker by 
the amount of acid that is absorbed by the active material of the 
plates in the formation of lead sulphate, which is a compound of 
acid and lead. This lead sulphate continues to increase in bulk, 
filling the pores of the plates, and as these pores are stopped up by 
the sulphate, the free circulation of the acid is retarded. Since 
the acid cannot reach the active material of the plates fast enough 
to maintain the normal action, the battery becomes less active. 


1 


i 


-'eI 


i 





EI.ECTRICAL EQUIPMENT 


620 


which is indicated by a rapid falling off in the voltage. Starting 
at slightly over 2 volts per cell when fully charged, this voltage 
will be maintained at normal discharge rates with but a slight drop, 
until the lead sulphate begins to fill the plates. As this occurs, 
the voltage gradually drops to 1.8 volts per cell and from that point 
on will drop very rapidly. A voltage of 1.7 volts per cell indicates 
practically complete discharge, or that the plates of the cell are 
filled with lead sulphate and that the battery should be placed on 
charge immediately. 

During the normal discharge, the amount of acid used from the 
electrolyte will cause the specific gravity of the solution to drop 
100 to 150 points, so that if the hydrometer showed a reading of 
1.280 when the cell was fully charged, it will indicate but 1.130 to 
1.180 when it is exhausted, or completely discharged. The electrolyte 
is then very weak; in fact, it is little more than pure water. Practically 
all of the available acid has been combined with the active material 
of the plates. While the acid and the lead combine with each other 
in difinite proportions in producing the current on discharge, it is 
naturally not possible to provide them in such quantities that both 
are wholly exhausted when the cell is fully discharged. Toward the 
end of the discharge, the electrolyte becomes so weak that it is no 
longer capable of producing current at a rate sufficient for any 
practical purpose. For this reason, an amount of acid in excess of 
that actually used in the plates during discharge is provided. This 
is likewise true of the active material. 

Capacity of a Battery. The amount of current that a cell will 
produce on discharge is known as its capacity and is measured 
in ampere hours. It is impossible to discharge from the cell as much 
current as was needed to charge it, the efficiency of the average cell 
of modern type when in good condition being 80 to 85 per cent, 
or possibly a little higher when at its best, i.e., after five or six 
discharges. In other words, if 100 ampere hours are required to 
charge a battery, only 80 to 85 ampere hours can be discharged 
from it. This ampere-hour capacity of the cell depends upon the 
type of plate used, the area of the plate, and the number of plates 
in the cell, i.e., total positive-plate area opposed to total negative- 
plate area. To accomplish this, both outside plates in a cell are 
made negative. The ampere-hour capacity of a battery, all the 


G30 


ELECTRICAL EQUIPMENT 


cells of which are connected up as a single series, is the same as that 
of any single cell in the series; as in connecting up dry cells in series, 
the current output is always that of a single cell, while the voltage 
of the current increases volts for each cell added to the series. In 
the case of the storage battery, it increases two volts for each cell. 

The capacity of the cell as thus expressed in ampere hours is 
based on its normal discharge rate or on a lower rate. For example, 
take a 100-ampere-hour battery. Such a battery will produce current 

at the rate of 1 am¬ 
pere for practically 100 
hours, 2 amperes for 50 
hours, or 5 amperes for 
20 hours; but as the dis¬ 
charge rate is increased 
beyond a certain point, 
the capacity of the bat- 
terv falls oft*. The batterv 

t- 4/ 

in question would not 
produce 50 amperes of 
current for 2 hours. This 
is because of the fact that 
the heavy discharge pro¬ 
duces lead sulphate so 
rapidly and in such large 
quantities that it quickly 
fills the pores of the 
active material and pre¬ 
vents further access of 
the acid to it. Thus, 
while it will not produce 
50 amperes of current for 2 hours on continuous discharge, it will be 
capable of a discharge as great or greater than this by considerable, if 
allowed periods of rest between. When on open circuit, the storage 
battery recuperates very rapidly. • It is for this reason that when 
trying to start the switch should never be kept closed for more than 
a few seconds at a time. Ten trials of 10 seconds each with a half¬ 
minute interval between them will exhaust the batterv less than will 
spinning the motor steadily for a minute and forty seconds. 



Fig. 454. Section of Willard Starting Battery, 
Showing Mud Space 












































































































































ELECTRICAL EQUIPMENT 


631 


Construction Details. For automobile starting and lighting 
service, the elements of the cells are placed in insulating supports 
in the bottom of the hard rubber jars and sealed in place. These 
supports hold the plates off the bottom of the jar several inches in 
the later types of starting batteries. Figs. 454 and 455 show sections 
of the Willard starter battery and another standard type This is 
known as the mud space and is designed to receive the accumulation 
of sediment consisting of the active material which is shaken off the 
plates in service. This ac¬ 
tive material is naturally a 
good electrical conductor, 
and if it were allowed to 
come in contact with the bot¬ 
toms of the groups of plates, 
it would short-circuit the 
cell. Sufficient space is usu-^ 
ally allowed under the plates 
to accommodate practically^ 
all of the active material that 
can be shed by the plates 
during the active life of the 
cell. In a battery having 
cells of this type, it is never 
necessary to wash the cells, 
as the elements themselves 
would require renewal be¬ 
fore the sediment could 
reach the bottom of the 
plates. 

In sealing the elements into the jar, a small opening is left for 
the purpose of adding distilled water as well as to permit the escape 
of the gas when the battery is charging. Except when being used 
for refilling the jars, this opening is closed by a soft rubber stopper 
which has a small perforation through which the hydrogen passes 
out of the cell when the latter is gassing, as explained later. The 
different cells of a battery are electrically connected by heavy lead 
straps, these strips being usually burned onto the plates by the 
lead-burning process.'' 



Fig. 455. Typical Starting Battery with Plates Cut 
Down, Showing Assembly 
















G32 


ELECTRICAL EQUIPMENT 


Edison Cell Not Available. It will be noted that the foregoing 
description has been confined entirely to the lead-plate type of storage 
battery and that no mention has been made of the Edison cell. The 
latter is not available for starting service on the automobile, because 
its internal resistance is too high to permit the extremely heavy 
discharge rate that is necessary. In extremely cold weather or where 
the engine is unusually stiff for other reasons, this may be as high 
as 300 amperes momentarily, while, under ordinary conditions, it 
will reach 150 to 200 amperes at the moment of closing the switch. 
The efficiency of the Edison cell also drops off very markedly in cold 

weather, though this is 
also true to a lesser extent 
of the lead-plate type. 

CARE OF THE BATTERY 
The following in¬ 


structions are given 
about in the order in 
which it is necessary to 
apply them in the care of 
a storage battery. 

Adding Distilled 
Water. In order to func¬ 
tion properly, the plates 
in the cells must be cov¬ 
ered by the electrolyte at 
all times to a depth of half an inch. Fig. 456 shows a handy method of 
determining this definitely. A small piece of glass tube, open at both 
ends, is inserted in the vent hole of the battery until it rests on the tops 
of the plates. A finger is then pressed tightly on top of the upper end 
of the tube, and the tube is withdrawn. It will bring with it at its 
lower end an amount of acid equivalent to the depth over the plates. 
This should always be returned to the same cell from which it was 
taken. The electrolyte consists of sulphuric acid and water. The 
acid does not evaporate, but the water does. The rapidity with 
which the water evaporates will depend upon the conditions of charg¬ 
ing. For example, if a car is constantly driven on long day runs and 
gets very little night use, the storage battery is likelv to be contin- 





Fig. 456. Diagram Showing Method of Measuring Height 
of Electrolyte over Plates 

Courtesy of U. S. Light and Heat Corporation, 
Niagara Falls, New York 
































































ELECTRICAL EQUIPMENT 


633 


ually overcharged and may need the addition of water to the elec¬ 
trolyte as often as every three days, whereas, in ordinary service, 
once a week would be sufficient. Even with intermittent use, the 
battery should not be allowed to run more than two weeks without 
an inspection of the level of the electrolyte and the addition of 
distilled water, if necessary. Distilled water is always specified, 
since the presence of impurities in the water would be harmful to 
the battery, this being particularly the case where they take the 
form of iron salts. Where it is not convenient to procure distilled 
or rain water in sufficient quantities, samples of the local water sup¬ 
ply may be submitted to any battery manufacturer for analysis. 

While it is necessary to maintain the electrolyte one-half inch 
over the plates, care must be taken not to exceed this, for, if filled 
above this level, the battery will flood when charged, owing to the 
solution with the increasing temperature. The best time for adding 
water is just before the car is to be taken out for several hours of use. 
It may be done most conveniently with a glass and rubber syringe 
of the type used with the hydrometer. Care should be taken when 
washing the car to see that no water is allowed to enter the battery 
box, as it is likely to short-circuit the cells across their lead connectors 
and to carry impurities into the cells themselves. 

Adding Acid. When the level of the electrolyte in the cell 
becomes low, it is, under normal conditions, caused by the evaporation 
of the water, and this loss should be replaced with water only. There 
being no loss of acid, it shoidd never he necessary to add acid to the 
electrolyte during the entire life of the battery. When a jar leaks or 
is accidentally upset, and some of the solution lost, the loss should be 
replaced with electrolyte of the same specific gravity as that remaining 
in the cell, and not with full strength acid nor with water alone. The 
former would make the solution too heavy, while the latter would 
make it too weak. Consequently, unless acid is actually known to 
have escaped from the cell, none should ever be added to it. Under 
the sections on the Hydrometer and Specific Gravity, further reasons 
are given why no acid or electrolyte should be added to the cell 
under normal conditions, and the causes which would seem to make 
the addition of acid necessary are explained. 

Hydrometer. Next to the regular addition of distilled water 
to the cells, the garage man will be called upon most frequently to 


G34 


ELECTRICAL EQUIPMENT 


test the condition of the cells with the hydrometer. This is termed 
taking the specific gravity and is one of the most important tests 
in connection with the care of the battery. The specific gravity of 
a liquid is determined by means of an instrument consisting of a 
weighted glass tube having a scale marked on it. This instrument is 
the hydrometer, and in distilled water at 60 degrees it should sink 
until the scale comes to rest at the surface of the liquid at the division 
1.000. The lighter the liquid, the further the instrument will sink 

in it; the heavier the liquid, the higher the 
instrument will float. For constant use in 
connection with the care of lighting and 
starting batteries, the hydrometer shown in 
Fig. 457 will be found the most convenient. 
Where the battery is located on the run¬ 
ning board of the car, the test piay be made 
without removing the syringe from the cell, 
but care must be taken to hold it vertical 
to prevent the hydrometer from sticking to 
the sides of the glass barrel. Wherever pos¬ 
sible, the reading should be made without 
removing the syringe from the vent hole of 
the cell, so that the electrolyte thus with¬ 
drawn may always be returned to the same 
cell. Where the battery is located in a posi¬ 
tion difficult of access, as under the floor 
boards, the syringe may be drawn full of 
electrolyte and then lifted out; as the soft 
rubber plug in the bottom of the glass barrel 
is in the form of a trap, when the instru¬ 
ment is held vertical, the solution will not 
run out while the reading is being taken. 

Failure to replace the. electrolyte in the same cell from which 
it was taken will result in destroying the uniformity of the cells. 
For example, if electrolyte has been withdrawn from cell No. 1 of 
the battery and, after taking the reading, it is put into cell No. 2, 
the amount taken from No. 1 must later be made up by adding water, 
and the solution will be that much weaker, while the electrolvte 
of No. 2 will be correspondingly stronger. 



Fig. 457. Syringe Hydrom¬ 
eter Set 











ELECTRICAL EQUIPMENT 


635 


Hydrometer Tests. In taking a hydrometer reading, first see 
that the instrument is not held by the sides of the glass syringe 
barrel; then note the level of the instrument in the liquid by looking 
at it from below, i.e., hold it up above the level of the eye. Reading 
the hydrometer in this way is found to give more accurate results 
than looking down upon it. While the hydrometer affords the best 
single indication of the condition of the battery—the cells should 
test 1.250 to 1.300 when fully charged and 1.150 when fully dis¬ 
charged, below which point they should never be allowed to go— 
there are conditions under which the instrument may be entirely 
misleading. For exarnple, when fresh distilled water is added to a 
cell to bring the solution up to the proper level, the additional water 
does not actually combine with the electrolyte until the cell has 
been on charge for some time. Consequently, if a hydrometer 
reading were taken of that particular cell just after the water had 
been added, the test would be misleading, as it would apparently 
show the cell to be nearer the fully discharged state than it actually 
was, owing to the low specific gravity of the electrolyte. If, on the 
other hand, fresh electrolyte or pure acid has been added to a cell 
just prior to taking readings, and without the knowledge, of the tester 
the reading would apparently shctw the battery to be fully charged, 
whereas the reverse might be the case. In this instance, the specific 
gravity would be higher than it should be. To determine accurately 
the condition of the cells in such circumstances, the hydrometer 
readings would have to be checked by making tests with the volt¬ 
meter, as described later. 

Under average conditions, however, the hydrometer alone will 
closely indicate the state of charge, and its use should always be 
resorted to whenever there is any question as to the condition of 
a battery. For instance, an irate owner will sometimes condemn the 
battery for failure of the starting motor to operate and will be 
absolutely positive that the battery has been fully charged, since he 
has been driving in daylight for hours.. The hydrometer reading will 
show at once whether the battery is charged or not. If it is not, it will 
indicate either that the generator, its regulator, or the battery ciit-out 
are not working properly, or that there i^ a short-circuit or a ground 
somewhere in the lighting or ignition circuits which permits the 
battery to discharge itself. Another more or less common complaint, 


636 


ELECTRICAL EQUIPMENT 


the cause of which may be definitely assigned one way or the other 
by the aid of the hydrometer is that “the battery is not holding 
its charge”. Except where it is allowed to stand for long periods 
without use, as where a car is laid up for a month or more, there is 
no substantial decrease in the capacity simply through standing, 
unless the battery is allowed to stand in a discharged condition. 

Consequently, the owner’s impression that the charge of the 
battery is mysteriously leaking away overnight through some short¬ 
coming of the cells themselves is not correct. If there is a fault, it 
is probably in the wiring; or a switch may have been left on inadvert¬ 
ently; or, as is very often the case, the car is not driven long enough 
in daylight to permit the generator to charge the battery sufficiently. 
When driving at night with all lights on, as is commonly the custom, 
the generator supplies very little current in excess of that required 
by the lamps. As a result, the battery receives but a fraction of 
its normal charge, so that one or two attempts to use the starting 
motor exhaust it. A hydrometer test made just before using the 
starting motor will show that there is only a small fraction of a charge 
in the cells, so that they are not capable of supplying sufficient current 
to turn the engine over longer than a few seconds. The hydrometer 
is equally valuable in indicating when a battery is being overcharged, 
though this is a condition which carries its own indication, known 
as gassing, which is described in detail under that head. 

Variations in Readings. Specific-gravity readings between 
1.275 and 1.300 indicate that the battery is fully charged; between 
1.200 and 1.225, that the battery is more than half discharged; 
between 1.150 and 1.200, that the battery is quickly nearing a fully 
discharged condition and must be recharged very shortly, otherwise 
injury will result. Below 1.150 the battery is entirely exhausted and 
must be recharged immediately to prevent the plates from becoming 
sulphated, as explained in the section covering that condition. 

Where the specific gravity in any cell tests more than 25 points 
lower than the average of the other cells in the battery, it is an 
indication that this cell is out of order. Dependence should not be 
placed, however, on a single reading where there is any question as 
to the specific gravity. Take several readings and average them. 
Variations in cell readings may be caused by internal short-circuits 
in the cell; by putting too much water in the cell and causing a loss 


ELECTRICAL EQUIPMENT 


637 


of electrolyte through flooding or overflowing; or by loss of electro¬ 
lyte from a cracked or leaky jar. Internal short-circuits may result 
from a broken separator or from an accumulation of sediment in the 
mud space of the jars reaching the bottom of the plates. 

Quite a substantial percentage of all the troubles experienced 
with starting batteries, which are only too often neglected until 
they give out, is caused by letting the electrolyte get too low in the 
jars. The effect of this is to weaken the battery, causing it to dis¬ 
charge more readily, and frequently resulting in harmful sulphating 
of the plates and injury to the separators. When such sulphating 
occurs, it permits the plates to come into contact with each other, 
and an internal short-circuit results. The importance of always 
maintaining the electrolyte one-half inch above the tops of the plates 
will be apparent from this. 

One of the most frequent causes of low electrolyte in a single 
cell is the presence of a cracked or leaky jar. If one of the cells 
requires more frequent addition of water than the others to maintain 
the level of its electrolyte, it is an indication that it is leaking. Where 
all the cells of a battery require the addition of water at unusually 
short intervals, it is an indication that the battery is being constantly 
overcharged. (See Gassing.) Unless a leaky jar is replaced 
immediately, the cell itself will be ruined, and it may cause serious 
damage to the remainder of the battery. Jars are often broken owing 
to the hold-down bolts or straps becoming loose, thus allowing the 
battery to jolt around on the running board, or they may be broken 
by freezing. The presence of a frozen cell in a battery shows that 
it has been allowed to stand in an undercharged condition in cold 
weather, as a fully charged cell will not freeze except at unusually 
low temperatures. 

Frozen Cells. In some cases, the cells may freeze without crack¬ 
ing the jars. This will be indicated by a great falling off in the 
efficiency of the cells that have suffered this injury, or in a totally 
discharged condition which cannot be remedied by continuous 
charging. In other words, the battery is dead and the plates are 
worthless except as scrap lead. In all cases where cells have been 
frozen, whether the jar has cracked or not, the plates must be 
replaced at once. It must always be borne in mind that low tempera¬ 
tures seriously affect the efficiency of the storage battery and that 


638 


ELECTRICAL EQUIPMENT 


care should be taken to keep it constantly in a charged condition. 
A variation in the temperature also affects the hydrometer readings 
themselves. The effect of the temperature on the hydrometer tests 
is explained mnder Adjusting the Specific Gravity. 

Low Cells. When one cell of the battery tests more than 25 
points below the specific gravity of the others, as shown by the 
average of several readings taken of each, it should be placed on 
charge separately from an outside source of current. This may be 
done without removing it from the car or disconnecting it from the 
other cells, since the charging leads may be clipped to its terminal 
posts. If no other facilities are available and direct-current service 
is at hand, use carbon lamps as a resistance in the manner illustrated 
on another page. As the normal charging rate of the average starting 
battery is 10 to 15 amperes or more, that many 32-c.p. carbon 
filament lamps may be used in the circuit. Where only alternating 
current is available, a small rectifier, as described under Charging 
from Outside Sources, will be found most convenient in garages 
not having enough of this work to warrant the installation of a 
motor-generator. After the low cell has been on charge for an hour 
or two, note whether or not its specific gravity is rising, by taking a 
hydrometer reading. If, after several hours of charging, its specific 
gravity has not risen to that of the other cells, it is an indication 
that there is something wrong with the cell, and it should be cut 
out. (See Replacing a Jar and Overhauling the Battery.) 

Adjusting the Specific Gravity. Except in such cases as those 
mentioned under Hydrometer, where water has been added to the 
electrolyte just before testing, or electrolyte has been added without 
the knowledge of the tester, specific gravity of the electrolyte is the 
best indication of the condition of the cell, and the treatment to be 
given should always be governed by it. As explained in the section 
on x4ction on Charge and Discharge, the acid of the electrolyte com¬ 
bines with the active material of the plates to produce the current on 
discharge. The further the cell is discharged the more acid there 
will be in the plates, and the less in the solution. Consequently, 
low-gravity readings practically always mean lack of acid in the 
solution, and that implies lack of charge. Unless there is something 
wrong with the cell, charging will restore the acid to the electrolyte 
and bring the specific-gravity readings up to normal. In case a jar 







ELECTRICAL EQUIPMENT 


639 


is leaking or has been overturned and lost some of its electrolyte, no 
amount of charging will bring its specific gravity up to the proper 
point. 

The gravity readings of the cells vary somewhat in summer and 
winter, and they also decrease with the age of the plates, but the 
battery will continue to give good service as long as its specific 
gravity rises to between 1.250 and 1.300 when fully charged. In case 
it rises above 1.300, there is an indication that excess acid has been 
added to the electrolyte, and this must be corrected by drawing off 
some of the electrolyte with the syringe and replacing it with distilled 
water. A gradually decreasing specific gravity in all the cells 
of a battery is an indication that sediment is accumulating in the 
bottom of the jars and that the battery, if of the old type with 
low mud space, requires washing; if of the later type with high 
mud space, that its elements require renewal. Before accepting 
this conclusion, however, make certain that the low reading is not 
due to insufficient charging. In actual practice, starter batteries 
seldom remain long enough in service without overhauling even 
to need washing. 

Many starter batteries are kept in an undercharged condition 
so constantly, owing to frequent use of the starting motor with but 
short periods of driving in between, that they should be put on 
charge from an outside source at regular intervals. In fact, this 
is the only method of determining definitely whether the battery 
itself is really at fault or whether it is the unfavorable conditions 
under which it is operating. Where the cells give a low reading, 
no attempt should ever be made to raise the specific gravity of 
the electrolyte by adding acid, until the battery has been subjected 
to a long slow charge. The maximum specific gravity of the electro¬ 
lyte is reached when all the acid combined in the active material 
of the plates has been driven out by the charging current. Adding 
acid will increase the specific gravity, but it will not increase the 
condition of charge; it will simply give a false indication of a charged 
condition. For example, if the electrolyte of a cell tested 1.225, 
and, without giving it a long charge, acid were added to bring the 
specific gravity up to 1.275, it would then rise to 1.325 if put on charge, 
showing that 50 points of acid had remained combined in the plates 
when the low readings were taken. 


640 


ELECTRICAL EQUIPMENT 


The necessity for adjusting the specific gravity of the electrolyte 
in a cell can only be determined by first bringing it to its true maxi¬ 
mum. To do this with a starter battery, it must be put on charge 
from an outside source at a low rate, say 5 amperes, and kept on 
charge continuously until tests show that the specific gravity of 
the electrolyte has ceased to rise. This may take more than twenty- 
four hours, and readings should be taken every hour or so, toward 
the end of the charge. Should the battery begin to gas violently 
while tests show that the specific gravity is still rising, the charging 
current should be reduced to stop the gassing, or, if necessary, 
stopped altogether for a short time and then renewed. 

If after this prolonged charge, the specific gravity is not more 
than 25 points below normal, some of the solution may be drawn 
off with the syringe and replaced with small quantities of 1.300 
electrolyte, which should be added very gradually to prevent bring¬ 
ing about an excess. Should the specific gravity be too high at 
the end of the charge, draw off some of the electrolyte and replace 
it with distilled water to the usual level of one-half inch over the 
plates. A charge of this kind is usually referred to as a conditioning 
charge and, given once a month, will be found very greatly to 
improve starter batteries that are constantly undercharged in service. 

Temperature Corrections, All specific-gravity readings mentioned 
are based upon a temperature of 70° F. of the electrolyte, and as 
the electrolyte, like most other substances, expands with the heat 
and contracts with the cold, its specific gravity is affected by variations 
of temperature. This, of course, does not affect its strength, but 
as its strength is judged by its specific gravity, the effect of the 
temperature must be taken into consideration when making the tests. 
The temperature in this connection is not that of the surrounding 
air but that of the electrolyte itself, and as the plates and solution 
of a battery increase in temperature under charge, the electrolyte 
may be 70° F. or higher, even though the outside air is close 
to zero. Consequently, the only method of checking this factor 
accurately is to insert a battery thermometer in the vent hole of the 
cell. If, on the other hand, the battery has been standing idle for 
some time in a cold place, the electrolyte has the same temperature 
as the surrounding air, and a hydrometer reading taken without 
a temperature correction would be very misleading. 







ELECTRICAL EQUIPMENT 


641 


For example, assume that the car is standing in a barn in which 
the temperature is 20° F. and that it has not been running for some 
time so that the electrolyte is as cold as the surrounding air. A 
hydrometer reading shows the specific gravity of the electrolyte to 
be 1.265, which would indicate that the battery was approximately 
fully charged. But the correction for temperature amounts to one 
point (.001) for each three degrees above or below 70° F., and in this 
case a difference of 50 degrees would have to be allowed for. This 
amounts to practically 18 points, and the specific gravity of the 
cells is 1.265 minus 18, or 1.247. The battery is accordingly three- 
quarters charged, instead of fully charged as the uncorrected reading 
would appear to indicate. The electrolyte contracts with the drop 
in temperature, and its specific gravity becomes correspondingly 
higher without any actual increase in its strength. The opposite 
condition will be found when the battery has commenced to gas 
so violently that the temperature of the electrolyte is raised to 
100° to 105° F. At the former figure there would be a difference 
of 30 degrees, or 10 points, to allow for, in which case a specific gravity 
reading of 1.265 would actually be 1.275. Hydrometer scales, with a 
a temperature scale showing at a glance the corresponding correction 
necessary, simplify the task of correcting the readings; but to do 
this properly a battery thermometer must be employed, as the 
temperature of the electrolyte itself is the only factor to be considered. 

Gassing. When an electric current is sent through a storage- 
battery cell, it immediately attacks the lead sulphate into which 
the active material of both the positive and the negative plates 
has been converted during the discharge and begins to reconvert 
it into peroxide of lead at the positive plate and into spongy metallic 
lead at the negative. As long as there is an ample supply of this 
lead sulphate on which the current may work, as in a fully discharged 
battery, the entire amperage being sent through the battery is restricted 
to carrying on this process. In other words, the current will always 
do the easiest thing first by following the path of least resistance. When 
the cell is in a discharged state, the easiest thing to do is to decompose 
the lead sulphate. As there is a comparatively large amount of 
this lead sulphate in a fully discharged battery, a correspondingly 
large amount of current can be used in charging at the start. But 
as the amount of sulphate progressively decreases with the charge. 


642 


ELECTRICAL EQUIPMENT 


a point is reached at which there is no longer sufficient sulphate 
remaining to utilize all the current that is passing through the cell. 

The excess current will then begin to do the next easiest thing, 
which is to decompose the water of the electrolyte and liberate 
hydrogen gas. This gassing is not owing to any defect in the battery, 
as some owners seem to think, but is simply the result of over¬ 
charging it. In one instance, a car owner condemned the starting 
battery with which his machine was equipped, for the reason that 
it was ‘‘always boiling”. In fact, it ‘‘boiled” itself to pieces and 
had to be replaced by the manufacturer of the car after only a few 
months of service; while, as a matter of fact, the conditions under 
which the car was driven were wholly responsible. It was used for 
long runs in the day time with infrequent stops, and was rarely run 
at night; therefore, the battery was continually charging but seldom 
had an opportunity to discharge. 

This erroneous impression is also closely interlinked with another 
that is equally common and equally harmful. This is that one of 
the functions of the battery cut-out is to break the circuit and prevent 
the battery from becoming overcharged. It is hardly necessary 
to add that this is not one of its functions, but that as long as the gen¬ 
erator is being driven above a certain speed, the cut-out will keep the 
battery in circuit, and the generator will continue to charge it. Its 
only purpose is to prevent the battery from discharging itself through 
the generator when the speed of the generator falls to a point where 
its voltage would be overcome by that of the battery unless the 
battery were automatically disconnected. The cut-out does not 
protect the battery from being overcharged; only the driver or the 
garage man can do that by noting the conditions under which the 
car is operated and taking precautions to prevent the battery 
from overcharging. 

Gassing is simply an indication that too much current is being 
sent into the battery. Another indication of the same condition 
is the necessity for refilling the cells with distilled water at very 
short intervals, as an excess charge raises the temperature of the 
electrolyte and causes rapid losses by evaporation. That is the 
reason why it is likely to be so harmful to the battery unless remedied, 
as if allowed to exceed 110° F., the active material is likely to be forced 
out of the grids, and the cells to be ruined. While it is essential 


ELECTRICAL EQUIPMENT 


643 


that the battery be fully charged at intervals and that it be always 
kept well charged, continuously overcharging it is likely to be as 
harmful as allowing it to stand undercharged. Where the conditions 
of service cannot be altered to remedy the trouble, the regulator 
of the generator should be adjusted to lower the charging rate, or, 
if nothing else will suffice, additional resistance, controlled by an 
independent switch, may be inserted in the charging circuit. (The 
U.S.L. system has a provision to safeguard the battery against 
overcharge, termed the touring switch.) 

Higher Charge Needed in Cold Weather. While the regulator 
of the generator is set by the manufacturer to give the best average 
results, and some makers warn the user against altering its adjustment, 
experience has demonstrated that a fixed adjustment of the regulation 
will not suffice for cars driven under all sorts of service conditions, 
nor for the same car as used at different seasons of the year. The 
efficiency of the storage battery is at its lowest in cold weather, 
which is the time when the demand upon it is greatest. A battery 
that would be constantly overcharged during the summer may not 
get more than sufficient current to keep it properly charged in 
winter, though driven under similar conditions in both seasons. 
On the other hand, a battery that is generally undercharged under 
summer conditions of driving will be practically useless in winter, 
as it will not have sufficient current to meet the demands upon it. 

It may be put* down as a simple and definite rule that if the 
battery of a starting system never reaches the gassing stage, it 
is constantly undercharged and is rapidly losing its efficiency, as 
the sulphate remaining on the plates becomes harder with age 
and prevents the circulation of the electrolyte. Even when in the 
best condition, the electrolyte cannot reach all of the active material 
in the plates, so that any reduction means a serious falling off. Like¬ 
wise, when a battery is constantly gassing, it is in a continuous 
state of overcharge and is apt to be entirely ruined in a comparatively 
short time. The danger from undercharging is known as sulphat- 
ing—the plates become covered with a hard coating of lead sulphate 
that the electrolyte cannot penetrate—while that from overcharging 
is due to the electrolyte and the plates reaching a dangerous tempera¬ 
ture (105° F. or over) at which the active material is apt to be stripped 
from the grids. The conditions of service, on the average, are such 


G44 


ELECTRICAL EQUIPMENT 


that a battery can seldom be kept in good condition for any length 
of time on the charging current from the generator alone. 

The hydrometer should be used frequently to keep track of 
its condition and, at least once a month, it should be given a long 
conditioning, or equalizing, charge, as it is variously termed. 
This charge is required because of the fact that, under ordinary 
conditions, a battery seldom receives a complete charge and that 
every time it is discharged without this being followed by a charge 
which is prolonged until the electrolyte has reached its maximum 
specific gravity, more lead sulphate accumulates in the plates. The 
object of the long charge is to convert this lead sulphate into peroxide 
of lead at the positive plate and into spongy metallic lead at the 
negative plate, as explained further under the head of Sulphating. 

Sulphating. At the end of a discharge, both sets of plates 
are covered with lead sulphate. This conversion of the active material 
of the plates into lead sulphate, which takes place during the discharge, 
is a normal reaction and, as such, occasions no damage. But if the 
cells are allowed to stand for any length of time in a discharged 
condition, the sulphate not only continues to increase in bulk, but 
becomes hard. It is also likely to turn white, so that white spots 
on the plates of a battery when it is dismantled are an indication that 
the cells have been neglected. In this condition, the plates have 
lost their porosity to a certain extent and it is correspondingly 
more difficult for the charging current to penetrate the active material. 
When a battery has stood in a discharged condition for any length 
of time, it becomes sulphated. The less current it has in it at the 
time and the longer it stands, the more likely it is to be seriously 
damaged. 

Where a car is used but little in the daytime, and then only 
for short runs with more or less frequent stops, the battery never 
has an opportunity to become fully charged. The demands of the 
starting motor and the lights are such that the battery is never 
more than half charged at any time. Consequently, there is always 
a certain proportion of the lead sulphate that is not reconverted, 
but which remains constantly in the plates. As already mentioned, 
this condition does not remain stationary; the sulphate increases 
in amount and the older portions of it harden. This represents 
a loss of capacity which finally reaches a point where the cells are 










ELECTRICAL EQUIPMENT 


G45 


no longer capable of supplying sufficient current (holding enough 
of the charge, as the owner usually puts it) to operate the starting 
motor. A battery that has been operating under conditions of this 
kind is not prepared for the winter’s service, which accounts for 
the great number of complaints about the poor service rendered 
by starting systems in the early part of every winter. As long as 
the weather is warm, the battery continues to supply sufficient 
current in spite of the abuse to which it is subjected, but when 
cold weather further reduces its efficiency, it is no longer able to 
meet the demand. 

The only method of preventing this and of remedying it after 
it has occurred is the equalizing charge metioned in the preceding 
section. Long continued and persistent charging at a low rate 
will cure practically any condition of sulphate, the time necessary 
being proportionate to the degree to which it has been allowed to 
extend. It is entirely a question of time, and, as a high rate would 
only produce gassing, which would be a disadvantage, the rate of 
charge must be low. In case the cells show any signs of gassing, 
the charge must be further reduced. 

Extra Time Necessary for Charging. The additional length of 
time necessary for charging a battery that has been constantly 
kept in an undercharged condition is strikingly illustrated by the 
following test made with an electric vehicle battery: The cells 
were charged to the maximum, and the specific gravity regulated 
to exactly 1.275 with the electrolyte just J inch above the tops.of 
the plates, this height being carefully marked. The battery was 
then discharged and recharged to 1.265 at the normal rate in each 
case. The specific gravity rose from 1.265 to 1.275 during the last 
hour and a half of the charge. During the following twelve weeks, 
the battery was charged and discharged daily, each charge being 
only to 1.265, thus leaving 10 points of acid still in the plates. At 
the end of the twelve weeks, the charge was continued to determine 
the time required to regain the 10 points and thus restore the specific 
gravity to the original 1.275. Eleven hours were needed, as compared 
with the hour and half needed at first. This test further illustrates 
why it is necessary to give a battery an occasional overcharge or 
equalizing charge to prevent it becoming sulphated. Had the battery 
in question been charged daily to its maximum of 1.275 and discharged 


646 


ELECTRICAL EQUIPMENT 


to the same extent during the twelve weeks, 9| hours of the last 
charge would have been saved. These periods of time, of course, 
refer to the charging of the electric-vehicle battery, but they indicate 
in a corresponding manner the loss of efficiency suffered by the start¬ 
ing battery owing to its being continually kept in an undercharged 
condition. 

Restoring Sulphated Battery. There are only three ways in 
which a battery may become sulphated: The first and most common 
of these is that it has not been properly charged; second, excess 
acid has been added to the electrolyte; third, an individual cell 
may become sulphated through an internal short-circuit or by drying 
out, as might be caused by failure to replace evaporation with 
water, or failure to replace promptly a cracked jar. The foregoing 
only holds good, however, where the sediment has not been allowed 
to reach the bottom of the plates, and where the level of the electrolyte 
has been properly maintained by replacing evaporation with 
distilled water. 

. To determine whether a battery is sulphated or not—it having 
been previously ascertained that it does not need cleaning (washing)— 
it should be removed from the car (the generator should not be run 
with the battery off the car without complying with the manufac¬ 
turer’s instructions in each case, usually to short-circuit or bridge 
certain terminals on the generator itself) and given an equalizing 
charge at its normal rate. The normal rate will usualy be found 
on the name plate of the battery. If the battery begins to gas at 
this rate, the rate must be reduced to prevent gassing, and lowered 
further each time the cells gas. Frequent hydrometer readings should 
be taken, and the charge should be continued as long as the specific 
gravity continues to increase. A battery is sulphated only when there 
is acid retained in the plates. When the specific gravity reaches 
its maximum, it indicates that there is no more sulphate to be acted 
upon, since, during the charge, the electrolyte receives acid from 
no other source. With a badly sulphated battery, the charge should 
be continued until there has been no further rise in the specific 
gravity of any of the cells for a period of at least twelve hours. Main¬ 
tain the level of the electrolyte at a constant height by adding pure 
water after each test with the hydrometer (if water were added just 
before taking readings, the water would rise to the top of the solution 










ELECTRICAL EQUIPMENT 


647 


and the reading would be valueless). With a battery on a long 
charge, the battery thermometer should be used at intervals to check 
the temperature of the electrolyte, and the hydrometer readings 
should be corrected in accordance with the temperature. 

Specific Gravity too High. Should the specific gravity of any 
of the cells rise above 1.300, draw off the electrolyte down to the top 
of the plates and put in as much distilled water as possible without 
flooding the cell. Continue the charge and, if the specific gravity 
again exceeds 1.300, this indicates that acid has been added during the 
previous operation of the battery. The electrolyte should then be 
emptied out and replaced with distilled water and the charge con¬ 
tinued. The battery can only be considered as restored to efficient 
working condition when there has been no rise in the specific gravity 
of any of the cells during a period of at least twelve hours of continu¬ 
ous charging. 

Upon completion of the treatment, the specific gravity of the 
electrolyte should be adjusted to its proper value of 1.280, using 
distilled water or 1.300 acid, as necessary. In cases where one cell 
has become sulphated while the balance of the battery is in good 
condition, it is usually an indication that there is a short-circuit or 
other internal' trouble in the cell, though this does not necessarily 
follow. To determine whether or not it is necessary to dismantle 
the cell, it may first be subjected to a prolonged charge, as above 
described. If its specific gravity rises to the usual maximum, the 
condition may be considered as remedied without taking the cell 
apart. It is the negative plate which requires the prolonged charge 
necessary to restore a sulphated battery. When sulphated, the 
active material is generally of light color and either hard and dense 
or granular and gritty, being easily disintegrated. Unless actually 
buckled or stripped of considerable of their active material, the 
positive plates are unchanged in appearance and can be restored 
to operative condition, though their life will be shortened by this 
abuse. Sulphated plates of either type should be handled as little 
as possible. By keeping close check with the hydrometer on the 
condition of the starting battery and, where it is not being kept in 
an overcharged condition constantly, giving it an equalizing charge 
once a month, the charge being continued until the cells no longer 
increase in specific gravity after a period of several hours, and the 


G48 


ELECTRICAL EQUIPMENT 


reading of all the cells being within at least 25 points of each other, 
sulphating may be avoided entirely. 

Internal Damage. This trouble is usually caused by a short- 
circuit, owing either to an accumulation of sediment reaching the 
plates or to the breaking of a separator, which may be caused by the 
active material being forced out of the grid, usually termed buckling, 
which is caused by overheating. It is important to be able to deter¬ 
mine whether or not the low efficiency of a certain cell is caused by 
internal trouble without having to dismantle the cell. The repair 
man’s most important aid for this class of work is the high-grade 
portable voltmeter mentioned in connection with other tests of the 
starting and lighting system. 

Voltage Tests. Under some conditions, the voltmeter will also 
indicate whether the battery is practically discharged or not, but, 
like the hydrometer, it should not be relied upon alone. To insure 
accuracy, it must be used in conjunction with the hydrometer. 
Since a variation as low as .1 (one-tenth) volt makes considerable 
difference in what the reading indicates regarding the condition of 
the battery, it will be apparent that a cheap and inaccurate voltmeter 
would be a detriment rather than an aid. The instrument illustrated 
in connection with tests of other parts of starting and lighting systems 
(see Delco) is of the type required for this service. Complete 
instructions for its use will be received with the instrument, and these 
must be followed very carefully to avoid injuring it. For example, 
on the three-volt scale, but one cell should be tested; attempting 
to test the voltage of more than one cell on this scale is apt to burn 
out the three-volt coil in the meter. The total voltage of the number 
of cells to be tested must never exceed the reading of the particular 
scale being used at the time; otherwise, the coil of the scale in question 
will suffer, and the burning out of one coil will make it necessary 
to rebuild the entire instrument. 

Clean Contacts Necessary. Where the voltage to be tested is 
so low, a very slight increase in the resistance will affect it considerably 
and thus destroy the accuracy of the reading. Make certain that 
the place on the connector selected for the contact point is clean 
and bright, and press the contact down on it firmly. To insure a 
clean bright contact point, use a fine file on the lead connector. 
The contact will be improved by filing the test points fairly sharp. 








ELECTRICAL EQUIPMENT 


649 


Even a thin film of dirt or a weak contact will increase the resistance 
to a point where the test is bound to be misleading. The positive 
terminal of the voltmeter must be brought into contact with the posi¬ 
tive terminal of the battery, and the negative terminal of the volt¬ 
meter with the negative of the battery. If the markings of the cell 
terminals are indistinct, connect the voltmeter across any one cell. 
In case the pointer butts up against the stop at the left instead of 
giving a reading, the connections are wrong and should be reversed; 
if the instrument shows a reading for one cell, the positive terminal 
of the voltmeter is in contact with the positive of the battery. This 
test can be made with a voltmeter without any risk of short-circuiting 
the cell, as the voltmeter is wound to a high resistance and will pass 

t 

very little current. Connecting an ammeter directly across a cell, how¬ 
ever, would short-circuit it and instantly burn out the instrument. 

How to Take Readings. It is one of the peculiarities of the 
storage cell that when on ‘‘open circuit”, i.e., not connected in 
circuit with a load of any kind, it will always show approximately 
two volts, regardless of whether it is almost fully charged or almost 
the reverse. Consequently, voltage readings taken when the battery 
is on open circuit, i.e., neither charging nor discharging, are valueless, 
except when a cell is out of order. Therefore, a load should be put 
on the battery before making these tests. This can be done by 
switching on all the lamps. With the lights on, connect the volt¬ 
meter, as already directed, and test the individual cells. If the 
battery is in good condition, the voltage readings, after the load 
has been on for about ten minutes, will be but slightly lower than 
if the battery were on open circuit. This should amount to about 
.1 (one-tenth) volt. Should one or more of the cells be completely 
discharged, the voltage of these cells will drop rapidly when the 
lamps are first switched on and, when a cell is out of order, will 
sometimes show a reverse reading. Where the battery is nearly 
discharged, the voltage of each cell will be considerably lower than 
if the battery were on open circuit, after the load has been on for 
five minutes. 

Detecting Deranged Cells. To distinguish the difference between 
cells that are merely discharged and those that are out of order, 
put the battery on charge, either from an outside source or 
by starting the engine, which should always be cranked by hand 


650 


ELECTRICAL EQUIPMENT 


when any battery trouble is suspected. Then test again with the 
voltmeter. If the voltage of each cell does not rise to approximately 
two volts after the battery has been on charge for ten minutes or 
more, it is an indication of internal trouble which can be remedied 
only by dismantling the cell. (See instructions under that heading.) 

Temperature Variations in Voltage Test. When making voltage 
tests, it must be borne in mind that the voltage of a cold battery rises 
slightly above normal on charge and falls below normal on discharge. 
The reverse is true of a warm battery in hot weather, i.e., the voltage 
will be slightly less than normal on charge and higher than normal 
on discharge. As explained in connection with hydrometer tests 
of the electrolyte, the normal temperature of the electrolyte may 
be regarded as 70° F., but this refers only to the temperature of 
the liquid itself as shown by the battery thermometer, and not to 
the temperature of the surrounding air. For the purpose of simple 
tests for condition, voltage readings on discharge are preferable, 
as variations in readings on charge mean little except to one expe¬ 
rienced in the handling of storage batteries. 

Joint Hydrometer and Voltmeter Tests. As already explained 
above, neither the hydrometer nor the voltmeter reading alone 
can always be taken as conclusive evidence of the condition of the 
battery. There are conditions under which one must be supple¬ 
mented by the other to obtain an accurate indication of the state 
of the battery. In making any of the joint tests described below, 
it is important to take into consideration the four points following: 

(1) The effect of temperature on both voltage and hydrometer 
readings. 

(2) Voltage readings should be taken only with the battery 
discharging, as voltage readings on an idle battery in good condition 
indicate little or nothing. 

(3) Never attempt to use the starting motor to supply a 
discharge load for the battery, because the discharge rate of the 
battery is so high while the starting motor is being used that even 
in a fully charged battery it will cause the voltage to drop rapidly. 

(4) The voltage of the charging current will cause the voltage 
of a battery in good condition to rise to normal or above the moment 
it is placed on charge, so that readings taken under such circumstances 
are not a good indication of the condition of the battery. 


ELECTRICAL EQUIPMENT 


651 


In any battery which is in good condition, the voltage of each 
cell at a normally low discharge rate, i.e., 5 to 10 amperes for a starter 
battery of the 6-volt type or slightly less for a higher voltage battery, 
will remain between 2.1 and 1.9 volts per cell until it begins to 
approach the discharged condition. A voltage of less than 1.9 volts 
per cell indicates either that the battery is nearly discharged or is 
in a bad condition. The same state is also indicated when the 
voltage drops rapidly after the load has been on for a few minutes. 
The following joint hydrometer and voltmeter tests issued by the 
Prest-O-Lite Company of Indianapolis will be found to cover 
the majority of cases met with in actual practice. 

(1) A voltage of 2 to 2.2 volts per cell with a hydrometer reading of 1.275 
to 1.300 indicates that the battery is fully charged and in good condition. 

(2) A voltage reading of less than 1.9 volts per cell, with a hydrometer 
reading of 1.200 or less indicates that the battery is almost completely discharged. 

(3) A voltage reading of 1.9 volts or less per cell, with a hydrometer 
reading of 1.220 or more, indicates that excess acid has been added to the cell. 
Under these conditions, lights will burn dimly, although the hydrometer reading 
alone would appear to indicate that the battery was more than half charged. 

(4) Regardless of voltage—high, low, or normal—any hydrometer reading 
of over 1.300 indicates that an excessive amount of acid has been added. 

(5) Where a low voltage reading is found, as mentioned in cases 2 and 
3, to determine whether the battery is in bad order or merely discharged, stop 
the discharge by switching off the load, and put the battery on charge, cranking 
the engine by hand, and note whether the voltage of each cell rises promptly to 
2 volts or more. If not, the cell is probably short-circuited or otherwise in bad 
condition. 

Cleaning a Battery. Electric vehicle batteries usually receive 
such careful and intelligent attention that the life of the battery 
is measured by the maximum number of charges and discharges of 
which the plates are capable under favorable conditions. To prevent 
any possibility of short-circuiting, a cell is cut out and opened after 
a certain number of discharges, and if the amount of sediment in 
the jar is approaching the danger point, the entire battery is opened 
and cleaned. With the old type starter cell, this would be necessary 
if the battery received the proper attention; with the modern or 
high mud-space type, cleaning is never necessary as the space is 
designed to accommodate all the active material that can fall from 
the plates without touching their under sides. As a matter of fact, 
the batteries of starting and lighting systems never last long enough 
to require cleaning out. They are either kept undercharged and 


G52 


ELECTRICAL EQUIPMENT 


thus become badly sulphated, or they are overcharged to a point 
where the temperature passes the danger mark frequently. When 
hot, the acid attacks and injures the wood separators so that the 
average life is about one year. Exceptions to this are found in 
those cases where the battery has been given proper attention, 
which results in unusually long life without the necessity of opening 
the cells for either cleaning or the insertion of new separators. These 
cases are so in the minority, however, that the battery manufacturers 
usually recommend that the car owner have his starting battery 
overhauled in the fall to put it in the best of condition for the winter 
as well as for the following year. Even where a battery has been 



Fig. 458. Drilling Off Connectors 

Courtesy of Electric Storage Battery Company, Philadelphia, Pennsylvania 


given conscientious attention, the conditions of charging on the 
automobile are likely to vary so radically that it will be found almost 
impossible to keep the cells in a good state. Consequently, it is 
considered the best practice to give all starter batteries an over¬ 
hauling once a year. The method of doing this is described in 
succeeding sections. 

Replacing a Jar. When a cell requires the addition of distilled 
water more often than the other cells of the battery, or does not 
test to the same specific gravity as the others, it is usually an indica¬ 
tion that there is a leak in the jar. Failure to give the same specific- 
gravity reading is not proof of this condition, as the cell may be 







ELECTRICAL EQUIPMENT 


653 


low from other causes, but the loss of electrolyte is certain evidence 
of it. The only remedy is to replace the jar at fault. 

After locating the cell in question, carefully mark the connectors 
so as to be sure to replace them the same way. Disconnect the 
cell from the others in the battery. This may be done either with 
the aid of brace and bit, which is used to drill down through the 
post of the connector. Fig. 458, or with a gasoline torch which should 


be applied carefully to the strap at the post. When the metal has 
become molten, pry the strap up on the post with a piece of wood. 
Do not use a screwdriver or other metal for this purpose as it is 
apt to short-circuit one or more of the cells. Care must also be 
taken not to apply so much heat that the post itself will be melted as 
this would make it difficult to reconnect the cell. For one not 
accustomed to handling the 
torch, it will be safer to drill out 
the post, as illustrated. Lift the 
complete cell out of the battery 
box and then use the torch to 
warm the jar around the top 
to soften the sealing compound 
that holds the cover. Fig. 459. 

Grip the jar between the feet, 
take hold of the two connectors 
and pull the element almost out 
of the jar. Fig. 460. Then grip 
the elements near the bottom 
to prevent the plates flaring out while transferring them to the new 
jar, taking care not to let the outside plates start down the outside 
of the jar. Fig. 461. After the element is in the new jar, reseal the 
cell by pressing the sealing compound into place with a hot putty 
knife. Fill the cell with 1.250 electrolyte to the proper point, the 
old electrolyte being discarded. 

Before replacing the connectors, clean both the post and the 
inside of the eye of the connector by scraping them smooth with 
a knife. When the connector has been placed in position, tap it 
down firmly over the post to insure good contact. To complete 
the connection, melt the lead of the connector and the post at the 
top so that they will run together^ and while the lead h still molten, 



Fig. 459. Softening Sealing Compound on Cell J 






654 


ELECTRICAL EQUIPMENT 


melt in some more lead until the eye of the connector is filled level. 
This is termed lead burning and is described at greater length in 
a succeeding section. Where no facilities are at hand for carrying 
it out, it may be done with an ordinary soldering copper. The 
copper is brought to a red heat so that all the tinning is burned 
off, and no fiux of any kind is used. The method of handling the 
soldering copper and the lead-burning strip to supply the extra 
metal required to fill the eye is shown in Fig. 462. 



Fig. 460. Lifting Elements out of Jar 
by Hand 


Fig. 461. Installing Elements 
in Jar 


Courtesy of Electric Storage Battery Company, Philadelphia, Pennsylvania 


Put the battery on charge from an outside source, and when 
the cells begin to gas freely, reduce the current to half the finishing 
rate given on the battery name plate and charge at this rate as long 
as there is any rise in the specific gravity of the electrolyte in 
this or any of the other cells. The maximum gravity has been 
reached when there has been no rise in the specific gravity for a 
period of three hours. If the gravity of the cell having the new jar 
is then over 1.280, draw off some of the electrolyte and replace it 
with distilled water. If the gravity is below 1.270, draw off some of 
the electrolyte and replace it with 1.300 electrolyte. If necessary 










ELECTRICAL EQUIPMENT 


655 


to put in 1.300 electrolyte, allow the battery to continue charging 
for about one-half hour longer at a rate sufficient to cause gassing, 
which will cause the stronger acid to become thoroughly mixed with 
the rest of the electrolyte in the cell. 

Overhauling the Battery. As already mentioned, it will be 
found desirable to overhaul the majority of starter batteries at 
least once a year. The expense to the car owner will be less than 



Fig. 462. Reburning Battery Connectors with Soldering Iron 
Courtesy of Electric Storage Battery Company, Philadelphia, Pennsylvania 


the cost of the frequent attention required by a run-down battery 
with complete renewal at no distant date, and the service rendered 
by the battery will be much improved. The best time of year to 
do this is in the late fall, so that the battery may be at its best during 
the cold weather. Before undertaking the work, have on hand a 
complete renewal set of rubber and wood separators as well as suf¬ 
ficient fresh acid of 1.300 specific gravity with which to mix fresh 
electrolyte. Use the good separators, particularly the rubber ones. 







656 


ELECTRICAL EQUIPMENT 


Dismounting Cells. Remove the connectors by drilling, heating, 
or pulling (in the same manner as a wheel is pulled), and loosen 
the jar covers by heating or running a hot putty knife around their 
edges so that they may be lifted off. The covers should be washed 
in hot water and then stacked one on top of the other with heavy 
weight on them to press them flat. Lift the jars out of the battery 
box and note whether any of them have been leaking. A cracked 
jar should of course be replaced. Treat one cell at a time, by 
pulling the element out of the jar with the aid of the pliers, meanwhile 
holding the jar with the feet. Lay the element on the bench and 




Fig. 463. Removing Old Separators Fig. 464. Pressing Negative Group 

from Elements 

Courtesy of Electric Storage Battery Company, Philadelphia, Pennsylvania 

spread the plates slightly to permit removing the separators, taking 
care not to injure the rubber sheets. Fig. 463. Separate the positive 
group from the negative. If the active material of the negative 
be swollen beyond the surface of the grid, press it back into position 
before it has a chance to dry, placing boards of suitable thickness 
between the plates and carefully squeezing the group between heavy 
boards in a vise or press, as shown in Fig. 464. Boards of sufficient 
size and thickness must be used between the plates or breakage 
will result. Charged negative plates will become hot in a short 
time when exposed to the air and, in this event, should be allowed 
to cool before reassembling. Remove any loose particles adhering 

























ELECTRICAL EQUIPMENT 


657 


to the positive plates by passing a smooth wood paddle over the 
surface but do not wash the positive plates. 

Treahng the Plates. If the positive plates show signs of buckling 
or stripping of the active matter, or if the negative plates have the 
light spotted appearance indicative of sulphating, it may be necessary 
to replace them altogether. In case sulphating appears to be the 
only trouble, the groups should be reassembled in an open jar with 
distilled water and given a long, slow charge, testing with the hydrom¬ 
eter at frequent intervals to note whether the specific gravity is 
rising or not. Twenty-four hours 
or more may be necessary for 
this charge, and two or three days 
will be nothing unusual. This 
charging, of course, is carried on 
from the lighting mains through 
a rectifier or a motor-generator, 
unless direct-current service is 
available. If it is necessary to 
prolong the charge over two or 
three days, and the specific grav¬ 
ity still continues to rise slowly, 
it may be preferable to replace 
the plates. 

Reassembling Battery. Wash 
all the sediment out of the jars, 
also wash and save the rubber 
sheets, unless they happen to be 
broken, but throw away the old 

wood separators. The rubber sheets should be placed in clean 
running water for about a quarter of an hour. Reassemble the 
positive and negative groups with the plates on edge in order to 
insert the separators. Place a rubber separator against the grooved 
side of a wood separator. Fig. 465, and insert a positive plate near 
the center of the element. The rubber sheet must be against the 
positive plate, and the wood separator against the negative plate. 
In this manner insert separators in all the spaces, working in both 
directions from the center. Care must be taken not to omit a sepa¬ 
rator as that would short-cireuit the cell. 











































































































































































































































































































































































m 


ELECTRICAL EQUIPMENT 


The separators should be practically flush with the bottoms of 
the plates to bring their tops against the hold-down below the strap, 
and must extend to or beyond the side edge of the plates. Grip 
the element near the bottom to prevent the plates flaring out while 
placing the element in the jar. Fill the cell to within one-half inch 
of the top of the jar, using electrolyte of 1.250 specific gravity. If 
the negative plates show signs of sulphating, but not enough to call 
for the special treatment mentioned above, use water instead of the 
electrolyte. After all of the cells have been given the same treatment 
and reassembled, return them to the battery box in their proper 
positions, so that the positive of each cell will be connected to the 
negative of the adjoining cell and connect temporarily by pressing 
the old connecting straps in place by hand. 

Checking the Connections. Put the battery on charge at its 
finishing rate (usually about 5 amperes) and, after charging about 
fifteen minutes, note the voltage of each cell. This is to insure 
having reconnected the cells properly with regard to their polarity. 
If this be the case, they should all read approximately 2 volts. Any 
cell that reads less is likely to have been connected backward. When 
the cells begin to gas freely and uniformly, take a hydrometer reading 
of each cell and a temperature reading of one of them. Reduce the 
current to one-half the finishing rate. Should the temperature of 
the electrolyte reach 100® F., reduce the charge, or interrupt it 
temporarily, to prevent the cells getting any hotter. Both hydrometer 
and temperature readings must be taken at regular intervals, say 
four to six hours apart, to determine if the specific gravity is still 
rising or if it has reached its maximum. Continue the charge and 
the readings until there has been no further rise for a period of at 
least twelve hours. Maintain the height of the electrolyte constant 
by adding water after each reading. (If water were added before 
the reading, it would not have time to mix with the electrolyte, 
and the reading would not be correct.) 

Should the specific gravity rise to about 1.300 in any cell, draw 
off the electrolyte down to the level of the tops of the plates and 
refill with as much water as possible without overflowing. Continue 
the charge, and if the specific gravity again exceeds 1.300, dump 
out all the electrolyte in that cell, replace it with water, and continue 
the charge. The charge can be considered complete only when 


ELECTRICAL EQUIPMENT 


659 



Fig. 466. Wiring Diagram for Discharging 
Battery through Rheostat 


/fmrneter 


there has been no rise in the gravity of any of the cells during a period 
of at least twelve hours of continuous charging. Upon completion 
of the charge, the electrolyte 
should have its specific gravity 
adjusted to its proper value 
(1.270 to 1.280) using water 
or 1.300 acid, as may be nec¬ 
essary, and the level of the 
electrolyte adjusted to a uni¬ 
form i inch above the plates. 

Discharge the battery at 
its normal discharge rate to 
determine if there are anv 
low cells caused by defective 
assembly. The normal dis¬ 
charge rate of the battery is 
usually given on its name 
plate. To discharge the bat¬ 
tery, the current may be 
passed through a rheostat, as 
in Fig. 466, or if no panel 
board of this type be avail¬ 
able, through a water resist¬ 
ance, as shown in Fig. 467. 

The resistance of a water rheo¬ 
stat increases with the dis¬ 
tance between its plates and 
decreases according to their 
proximity and to the degree 
of conductivity of the water 
itself. If the resistance is 
too high with the plates close 
together, add a little acid to 
the water. It will be neces¬ 
sary, of course, to have an 
ammeter in the circuit to show the rate at which the battery is 
discharging. In case any of the cells are low, owing to being assem¬ 
bled defectively or connected with their polarity reversed, as shown 



Weak ^/eetrolyte 
Weefges /orHofc/tna y 

euAere /Jef/u3feci 


Fig. 467. Wiring Diagram for Discharging 
Battery through Water Resistance 























































































660 


ELECTRICAL EQUIPMENT 


by the voltmeter test (they should all register two volts or slightly 
over at the beginning of the discharge and shouM fall off slowly) such 
cells should be remedied at once. Recharge the battery and then 
remove the temporary connectors, wipe the inside edges of the jars 
dry, and put the rubber covers in place. Heat the sealing compound 
which is supplied for this purpose and apply around the edges of the 
covers, smoothing it down with a hot putty knife. Care must be 
taken not to burn the sealing compound when heating it. 

Reconnecting Cells. If the old lead connecting straps have been 
removed carefully, they may be used again, though in many cases 
it will be found preferable to employ new straps. Before putting 
the straps in place, scrape the posts clean with a knife and clean 
out the eyes of the straps themselves. When the connectors have 
been put in place, tap them down firmly to insure good contact. 
Before reburning the connectors in place, test each cell with a low- 
reading voltmeter to make certain that the cells have been connected 
in the right direction, i.e., that their polarity has not been reversed. 
It is not sufficient to note that the voltage of each cell is correct, 
i.e., 2 volts per cell or over, but care must be taken also to note that 
it is in the right direction. With a voltmeter having a needle that 
moves in both directions from zero, one polarity will be evidenced 
by the needle moving over the scale to the right of the neutral line, 
while if the polarity be reversed, the needle will move to the left. 
One cell having the proper polarity should accordingly be tested 
and then, to be correct, the remaining cells should cause the needle 
to move in the same direction and to approximate the same voltage 
when the instrument leads are held to the same terminals in the 
same way for each. Where the voltmeter needle can move in but 
one direction, i.e., to the right, a change of polarity will be indicated 
by the needle of the instrument attempting to move to the left 
and, in so doing, butting up against the stop provided to prevent 
this. Complete the reassembly of the cells by burning the connectors 
together, as detailed under the head of Lead Burning. 

Renewals. In many cases it will be found necessary upon 
overhauling a battery to renew the elements. These may be purchased 
either as loose plates or as groups ready to assemble in the battery. 
Except in garages doing a large amount of this work, it will not 
be advisable to buy the loose plates and burn them into groups. 


ELECTRICAL EQUIPMENT 


661 


The new groups should be assembled with rubber sheets and wood 
separators, as directed in overhauling the battery, the jars filled 
with fresh electrolyte of the proper specific gravity and the battery 
given a test charge and discharge with temporary connections. The 
electrolyte should be of 1.250 specific gravity, or seven parts of 
water to two of pure sulphuric acid by volume. If the test charge 
has been carried to a point where the specific gravity has ceased to 
rise for several hours, and the discharge shows no defectively 
assembled cells, the cells may be permanently connected. 

Lead Burning. Type of Outfit. In the manufacture of storage 
batteries, and in garages where a large number of batteries are 



Fig. 468. Arc-Welding Outfit for Burning Connections 


maintained, a hydrogen-gas apparatus is employed for this purpose. 
For the electric-car owner or the garage doing a comparatively small 
amount of battery repair work, the Electric Storage Battery Com¬ 
pany has placed an arc lead-burning outfit on the market. This 
is low in first cost and, with a little practice, good results can be 
obtained with it. As the battery itself supplies the power neces¬ 
sary, the only material required is the lead in the form of a fiexible 
strip or heavy wire. The complete outfit is illustrated in Fig. 468. 
At one end is the clamp for making electrical connection, while at 
the other is a clamp of different form having an insulated handle 
and holding a one-fourth inch carbon rod. The two are electrically 





G62 


ELECTRICAL EQUIPMENT 


connected by a flexible cable. This simple outfit can be employed 
in two ways, the second being preferable for the beginner, at least 
until sufficient amount of skill has been acquired to use the arc 
without danger of melting the straps. 

First Method of Burning. In the first method, a potential of 
from 28 to 30 volts (12 to 15 cells) is required. The clamp should, 
therefore, be fastened to the positive pole of the twelfth to the 
fifteenth cell away from the joint to be burned, counting toward the 
negative terminal of the battery. The carbon then forms the negative 
terminal of the circuit. Otherwise particles of carbon will be carried 
into the joint, as the carbon rod quickly disintegrates when it forms 
the positive pole. The carbon should project 3 or 4 inches from the 
holder. The surfaces of the parts to be burned should be scraped 
clean and bright, and small pieces of clean lead about i to J inch 
square provided for filling the joint. The carbon is then touched to 
the strap to be burned and immediately withdrawn, forming an 
electric arc which melts the lead very rapidly. By moving the carbon 
back and forth the arc is made to travel over the joint as desired, the 
small pieces of lead being dropped in to fill the gap as required. 
Owing to the high temperature generated, the work must be carried 
out very quickly, otherwise the whole strap is liable to melt and run. 

As this method is difficult and requires practice to secure good 
results, the beginner should try his hand on some scrap pieces of 
lead before attempting to operate on a cell. Its advantages are 
that when properly carried out it takes but a short time to do the 
work, and the result is a neat and workmanlike joint. It is extremely 
hard on the eyes, however, and should never be attempted without 
wearing smoked or colored glasses, and even with this protection 
the eyes should be directed away from the work as much as possible. 

Second Method of Burning. The second method, utilizing the 
hot point of the carbon rod instead of the arc, is recommended for 
general practice. Scrape the parts to be joined and connect the 
clamp between the third and fourth cells from the joint. With this 
method it is not necessary to determine the polarity of the carbon. 
The latter is simply touched to the joint and held there; on account 
of the heavy flow of current it rapidly becomes red and then white 
hot. By moving it around and always keeping it in contact with 
the metal, the joint can be puddled. To supply lead to fill the joint. 


ELECTRICAL EQUIPMENT 


663 


an ordinary lead-burning strip can be used, simply introducing the 
end into the puddle of molten lead, touching the hot carbon. The 
carbon projecting out of the holder should be only one inch, or even 
less, in length. After the joint has been made, it can be smoothed 
off by running the carbon over it a second time. 

Use of Forms to Cover Joint. In joining a strap which has been 
cut in the center, it is best to make a form around the strap by means 
of a piece of asbestos sheeting soaked in water and fastened around 
the strap in the shape of a cup, which will prevent the lead from 
running down. It will be found that sheet asbestos paper is thick 
enough, but it should be fairly wet when applied. By this means a 
neat joint can be easily made. The asbestos will adhere very tightly 
to the metal owing to the heat, but can be removed by wetting it 
again. When burning a pillar post to a strap, a form may be made 
around the end of the strap in the same manner, though this is not 
necessary if reasonable care is used. Two or three pieces of j^-inch 
strap iron about one inch wide, and some iron nuts about one inch 
square are also of service in making the joint, the strap iron to 
be used under the joints, and the nuts at the side or ends to confine 
the molten lead. Clay can also be used in place of asbestos, wetting 
it to a stiff paste. As the holder is liable to become so hot from 
constant use as to damage the insulation, besides making it uncom¬ 
fortable to hold, a pail of water should be handy, and the carbon 
dipped into it from time to time. This will not affect its operation 
in any way, as the carbon becomes hot again immediately the current 
passes through it. 

Illuminating Gas Outfit. Heretofore it has not been possible to 
do good work in lead burning with illuminating gas, but a special 
type of burner has recently been perfected by the Electric Storage 
Battery Company, which permits the use of illuminating gas with 
satisfactory results. The outfit consists of a special burning tip and 
mixing valve. Sufficient i%^-inch rubber hose should be provided, and 
the rubber should be wired firmly to the corrugated connections. Fig. 
469, as the air is used at a comparatively high pressure. A supply of 
compressed air is necessary, the proper pressure ranging from 5 to 10 
pounds, depending upon the length of hose and the size of the parts to 
be burned. When air from a compressor used for pumping tires is 
utilized for this purpose, a suitable reducing valve must be introduced 


664 


ELECTRICAL EQUIPMENT 


in the supply line. This outfit is designed for use with ordinary 
illuminating gas and cannot be employed with natural gas. 

Connect the air hose to the right-hand cock and the gas hose to 
the left-hand cock. The leader hose, about five or six feet long, is 
connected to the lower pipe and to the upper end of the burning tip. 
When the air pressure at the source is properly adjusted, close the 
air cock and turn the gas cock on full. Light the gas at the tip and 
turn on the air. If the flame blows out, reduce the air pressure, 
preferably at the source. With the gas turned on full, the flame 



Fig. 469. Lead-Burning Outfit for Use with Illuminating Gas 
Courtesy of Electric Storage Battery Company, 

Philadelphia, Pennsylvania 

will have a ragged appearance and show a waist about J inch from 
the end of the tip, the flame converging there and spreading out 
beyond. Such a flame is not for lead burning. 

Slowly turn the gas off until the outer portion at the waist 
breaks and spreads with an inner tongue of flame issuing through the 
outer ring. Phe flame will now have a greenish color and is properly 
adjusted for burning. If the gas is turned off further or if too much 











ELECTRICAL EQUIPMENT 


665 


air is turned on, the flame assumes a blue color gradually becoming 
invisible and is then deficient in heating power. When properly 
adjusted, the hottest part of the flame is just past the end of the inner 
point. Do not hold the flame too close to the work when burning, 
as its heating effect is greatly reduced and the flame is spread so as to 
make control difficult. The burning tip has at its lower end an 
outer sleeve and lock nut; this sleeve can be taken off in case any 
of the holes in the tip become clogged. The position of this sleeve 
is adjustable, the best position varying with the pressure of the 
flame, and it should be determined by experiment. 

Hydrogen Gas Outfit. Hydrogen gas gives a hotter flame and 
therefore permits of more rapid work, so that where burning is done 
on a large scale, it is still preferred. The essentials of such an outfit 
are: first, a hydrogen generator; second, a method of producing air 
pressure at approximately 2 pounds to the square inch; and third, 
the usual pipe and tips for burning. If hydrogen gas is purchased in a 
tank and compressed air is available, only the blowpipe, tips, and a 
reducing valve on the air line are necessary. • This is an expensive 
method to purchase hydrogen, however, so that it is usually generated, 
and a water bottle is needed between the generator and the blowpipe 
to wash the gas and to prevent the flame from traveling back to the 
generator. 

For this purpose hydrogen gas is generated by placing zinc in a 
sulphuric-acid solution. The generator usually employed for vehicle- 
battery burning requires 50 pounds of zinc, 2 gallons of sulphuric 
acid, and 9 gallons of water for a charge. Where no compressed-air 
supply is available, an air pump and an air tank for equalizing the 
pressure must be used. An outfit of this kind is shown in Fig. 470. 
In preparing the generator for use, connect up as shown in this cut, 
taking care that the hose from the generator is connected to the 
nipple of the water bottle L. Have the water bottle one-half to 
two-thirds full and immerse it in a pail of cold water up to its neck. 
Replace the water in the pail whenever it becomes warm. Have stop 
cock N closed.. Put the required amount of zinc, which has been 
broken into pieces small enough to pass through the opening C, 
into the lower reservoir. Put on cap A and screw down with clamp D, 
being sure that the rubber drainage stopper H is well secured in 
place. Pour the proper amount of water into reservoir A and then 


666 


ELECTRICAL EQUIPMENT 


pour in the acid, taking care to avoid splashing. Always your the 
water in first. 

In running the hose from K to N, arrange it so that there will 
be no low points for the water of condensation to collect in; in other 
words, this hose should drain back at every point to the water bottle. 
If, however, water should collect in the hose to such an extent as to 
interfere with the flame and it cannot readily be drained off, kink the 
hose between T and U and detach it from K; close the stop cock at 
W and pump until a strong pressure is obtained in the tank; then close 



Fig. 470. Diagram of Lead-Burning Outfit, Using Hydrogen Gas 


the cock at V, opening those at S and N and, finally, quickly open W; 
the pressure in the air tank will then force the water out of the hose. 
The length of the hose from T to U should be such that the mixing 
cocks at S and N are always within easy reach of the man handling 
the flame 

In preparing the flame for burning, close the air cock at S and 
open N wide, hold a match to the gas until it lights, then add air 
and adjust the gas cock slowly, turning toward the closed position 
until the flame, when tried on a piece of lead, melts the metal and 
leaves a clean surface. The tip to be used depends on the work, but 
most vehicle-battery work is dene with the medium tip. Replenish 










































ELECTRICAL EQUIPMENT 


667 


the zinc every few days, keeping it up to the required amount. When 
a charge is exhausted or the generator is to be laid up for the night, 
the old solution should be drawn off before making up a new charge 
and the generator thoroughly flushed out by running water through A. 
The new charge should not be put in until the generator is to be used 
again. To empty the generator, first pull off the hose at the nipple 
K, then at E, and finally the rubber plug at II. Care should be 
taken not to allow the solution to splash on anything and not to 
dump the generator where the contents will damage cement, asphalt, 
or wood walks. 

Installing New Battery. In not a few instances, it will be neces¬ 
sary to renew the entire battery. As received from the manufacturer, 
the battery is in a charged condition, i.e., it was fully charged just 
previous to being shipped, but it must be inspected and tested before 
being installed on the car. Care must be taken in unpacking it to 
avoid spilling any of the electrolyte. After cleaning off the packing 
from the tops of the cells, take out the rubber plugs and see that the 
electrolyte is ^ inch over the plates. If it is uniformly or approxi¬ 
mately below the proper level in all the cells, this is simply the loss 
due to evaporation. But if low in only one or two cells, this is 
evidently caused by loss of electrolyte. In case this loss has resulted 
from the case being turned over in shipment, it will be indicated 
by the presence of acid on the packing on top of the battery (the 
acid does not evaporate), and some of the electrolyte will have 
been lost from all the cells. Replace the amount lost by refilling the 
cells with electrolyte of 1.250 specific gravity, as already directed. 

In case the loss of electrolyte is caused by a cracked or broken 
jar, the packing under the battery will be wet. Replace the broken 
jar as instructed in the directions under that heading and add sufficient 
electrolyte of 1.250 specific gravity to make up for the loss. Should 
it be found, after replacing the broken jar and giving the battery 
an equalizing charge, that the specific gravity does not reach approxi¬ 
mately 1.275, it is due to not having replaced the same amount of 
acid as was spilled. To adjust this, draw off the electrolyte from 
the cell with the syringe and add water or 1.300 acid to bring the 
specific gravity to between 1.270 and 1.280. 

Storing a Battery. There is an amusingly erroneous idea 
prevalent to some extent that the charge of a storage battery is 


668 


ELECTRICAL EQUIPMENT 


represented by its electrolyte; that pouring off the electrolyte takes 
takes the charge with it; that, in case it is desired to store a battery, 
all that is necessary is to pour off the electrolyte and store the empty 
battery and the solution separately; and when it is desired to put 
the battery back in commission, it is then only necessary to pour 
the electrolyte back int6 the cells and, presto! they are ready to 
start the engine right away. Unfortunately for this theory, the charge 
is in the active material of the plates and not in the electrolyte. 

It is frequently necessary to allow the battery to remain idle 
for a considerable length of time, in which case it should be put 
out of commission. If the battery itself is in good condition at 
the time and if it may be wanted for service again at short notice, 
this need only consist of giving it a long equalizing charge until 
the specific gravity has ceased to rise for several hours, then filling 
the cells to the top with distilled water and putting the battery away 
in a handy place. It should be given a freshening charge every 
two weeks or, at least, as often as once a month. If it is actually 
to be stored, there are two ways of doing this. 

One is known as the wet storage method, and the other as 
the dry, the one to be adopted depending upon the condition of the 
battery and the length of time it is to be out of commission. The 
wet storage method is usually applied to any battery that is to be 
out of commission less than a year, provided that it will not soon 
require repairs necessitating dismantling it. The dry storage method 
is used for any battery that is to be out of commission for more than 
a year, regardless of its condition, and it is also applied to any battery 
that will shortly require repairs necessitating its dismantling. It 
will be apparent that this last-named class includes most starter 
batteries after they have seen several months of service, so that the 
majority can be placed in dry storage when necessary to put them 
out of commission. 

Examine the conditions of the plates and the separators and 
also the amount of sediment in the bottom of the jars. If it is found 
that there is very little sediment and the plates and separators are 
in sufficiently good condition to give considerable additional service, 
the battery may be put into wet storage by giving it an equalizing 
charge and covering it to exclude dust. Replace evaporation 
periodically to maintain the level of the electrolyte J inch above the 


ELECTRICAL EQUIPMENT 


669 


tops of the plates. At least once every four months, charge the 
battery at one-half its normal finishing rate (see name plate on 
battery box) until all the cells have gassed continuously for at least 
three hours. Any cells not gassing should be examined, and the 
trouble remedied. 

When examination shows that the battery will soon require 
dismantling, it should be put into dry storage. Dismantle the cells 
in accordance with the instructions already given. If the positive 
plates show much wear, they should be scrapped; if not, remove 
any loose particles adhering to them by passing a smooth wood 
paddle over the surface, but do not wash the 'positive plates. Charged 
negative plates will become hot in a short time when exposed to 
the air. They should be allowed to stand in the air until cooled. 

Empty all the electrolyte out of the jars into a glass or glazed 
earthenware jar or a lead-lined tank and save it for giving the negative 
plates their final treatment before storage. Wash all the sediment 
out of the jars and wash the rubber separators carefully, then dry 
them and tie them in bundles. Place the positive groups together 
in pairs, put them in the jars, and store them away. Then put the 
negative groups together in the same way, place them in the remaining 
jars, and cover them with the electrolyte saved for the purpose, 
allowing them to stand in it for five hours, at least. Then pour off 
the electrolyte, which may now be discarded, and store away the 
jars containing the negatives. If the negative plates show any 
bulging of the active material, they should be subjected to the pressing 
treatment first, using boards and a vise, as described in a previous 
section. All of the jars should be well covered to exclude dust. 

Make a memorandum of the amount of material required to 
reassemble the battery, and, when ordering this, provide for extra 
jars and covers, extra rubber separators, and an entire lot of wood 
separators with a sufficient excess to take care of breakage in handling. 
Unless the old connectors were carefully removed, order a new set. 
When a battery is put in storage, it is well to advise the owner in 
regard to the material necessary to reassemble, and to request at least 
a month’s notice to procure it. 

Charging from Outside Source. Theoretically at least, the 
starter battery on the automobile should be kept in an ideal condition. 
It is constantly under charge while the car is running at anything 


670 


ELECTRICAL EQUIPMENT 


except the lowest starting speeds and should accordingly always 
be fully charged. The generator is designed to take care of the 
storage battery and usually has sufficient capacity to light all the 
lamps in addition. Practice, however, does not bear out this 
theoretical view of the favorable conditions under which the starter 
battery is supposed to operate. It will be apparent at the very 
outset that the method of charging and discharging is not beneficial. 
To insure long life to a storage battery, it should be fully charged 
and then discharged to at least seventy-five per cent of its maximum 
capacity before recharging. It should never be allowed to stand 
discharged for any length of time. If exhausted, it should be 
recharged immediately. It should not be charged to half its capacity 
and then discharged. It should not be'overcharged to the point 
where it continues to gas violently nor where its temperature exceeds 
100° F. 

All of these are things that should not be done to the storage 
battery, but it will take only a little experience to enable the garage 
man to recognize that all these are things which are constantly being 
done to the majority of storage batteries on gasoline automobiles. 
Most batteries receive treatment that reaches one extreme or the 
other, though it will be apparent that the middle course is almost 
as injurious to the battery. Either a battery is constantly kept 
undercharged so that it has insufficient charge to spin the engine 
more than once, and its operation is accordingly unsatisfactory, or 
it is constantly kept overcharged with the result that the hot acid 
makes comparatively short work of the plates, and they must be 
renewed in considerably less than a year of service. The mean course 
between these two is found in the case of the battery that is only 
charged to about half its capacity before being discharged again by 
the use of the starting motor. This treatment results in sulphating. 

To keep the storage battery of the starting system in anything 
like efficient operating condition, it cannot be left on the running 
board with nothing but the generator of the starting and lighting 
system to charge it. Hydrometer and voltage tests will be valueless 
unless the conditions they indicate are remedied, and this cannot 
be done with the car generator as the sole source of charging current. 
Here is a typical instance: The battery is in good condition and it 
is fully charged. On a cold morning, it is drawn on intermittently 


ELECTRICAL EQUIPMENT 


671 


for almost fifteen minutes by the starting motor before the engine 
fires. As a result, it is practically discharged. The car is driven only 
a few miles, stopped and after a rest started again. What charge 
the battery received by the short run is again lost. The car is run 
for a little longer time and returned to the garage. The battery 
has received about one-fourth its normal charge. It stands this 
way for several days. 

The weather being warmer, the engine starts in a much shorter 
time, but not before the starting motor has exhausted the small 
amount of charge in the battery. It is not run enough that day to 
charge the battery nor when taken out again that night, as all the 
lights are switched on, and under such conditions the battery receives 
very little current. Multiply this treatment by five or ten repre¬ 
senting the number of days the car is driven during the month. 
At the end of that time, the battery no longer has sufficient charge 
to operate the starting motor at all and is condemned, as usual, 
by the car owner as being worthless. This is only one instance of 
many that are so similar that a few changes in detail would cover 
them all. No battery ever made could possibly operate efficiently 
under such conditions. After the car in question had been used a 
few days, a hydrometer test of the battery would have indicated 
its need of charging. 

Equalizing Charges Necessary. Even where a battery receives 
almost 100 per cent of its normal charge before being discharged again, 
there will be numerous occasions on which the charge is not carried 
to completion. As mentioned under the head of Sulphating, 
that means so much acid left in the plates at the end of the charge. 
That acid represents lead sulphate which continues to increase in 
quantity as long as the acid remains in contact with the active 
material. To drive it out of the active material into the electrolyte, 
which is the function of charging, the charge must be carried to 
completion. This is termed an equalizing charge, and it should be 
given not oftener than once in two weeks, but at least once a month. 
To do this, it is necessary to charge the battery from an outside 
source, as it is seldom convenient to run the engine for the long 
period of time needed to complete such a charge. Except in cases 
where the battery is chronically overcharged, as indicated by its 
violent and continued gassing, it will usually be found necessary 



672 


ELECTRICAL EQUIPMENT 


to give it an equalizing charge once a month. The constantly over¬ 
charged condition is quite as injurious as its opposite, and it can be 
cured only by cutting down the output of the generator or increasing 
the demand upon the battery for current. 

Methods of Charging. The apparatus employed for charging 
starter batteries will naturally vary in accordance with the number 
that are looked after in the garage. It may range from the makeshift 
consisting of a bank of lamps up to an elaborate panel board designed 
to provide charging connections for a dozen or more batteries at once. 
Where direct current is available—and only a few starter batteries 
need this attention—a bank of lamps in connection with a fused 
double-pole switch will be found to fill all the requirements. Note 
the charging rate (finishing) given on the name plate of the battery 
and make the number of lamps in accordance. A 32 c.p. in the 
circuit is practically the equivalent of one ampere of current entering 
the battery, i.e., it requires one ampere to light a lamp of this size 
and type (carbon filament) to incandescence. A number of standard 
lamp sockets should be mounted on a board, connected in multiple, 
and the group connected in series with the switch and the battery. 
(See illustration in resume of questions and answers on the battery.) 
As many lamps as necessary may then be screwed into the sockets. 
The more current needed, the more lamps and the higher power 
lamps will be necessary. Tungsten lamps may be employed as well 
as the carbon-filament type, but as they take so much less current, 
lamps of higher candle power will be needed. For example, to 
replace a 32-c.p. carbon-filament lamp, a 100-watt tungsten lamp 
will be required. 

t Charging in Series for Economy. Where several starter batteries 
are to be charged at the same time, it will be found more economical 
to connect them in series and charge them all at once. The difference 
between the 110-volt potential of the lighting mains and the 6 to 8 
volts needed to charge a single three-cell battery represents that 
much waste, as the drop in voltage has to be dissipated, through a 
resistance, to no purpose. In this way, any number of 6-volt storage 
batteries, up to twelve, can be charged from a 110-volt circuit (direct- 
current) with the same expenditure of current as would be required 
for a single battery. This is owing to the fact that, in any storage 
battery, the capacity of the battery is the capacity of one cell. 


ELECTRICAL EQUIPMENT 


673 


where all are connected in series. Consequently, it will take 10 to 
15 amperes to charge one 6-volt battery from the lighting circuit, 
and when several more units of the same size are connected in series 
with it, the current consumption will still be the same, but a smaller 
part of the voltage will have to be wasted through a resistance. 

Motor=Qenerator. Direct current will be found available in 
comparatively few places to-day, so that some means of rectifying 
an alternating current, in order to use it for charging batteries, will 
be necessary. Where quite a number of batteries are to be cared 
for, the motor-generator will be found to give the highest efficiency, 
besides proving more economical in other ways. As its name indicates, 
it consists of a motor wound for alternating current and fed from 
the supply mains of the garage, and a direct-current generator which 
is driven at its normal generating speed by the a.c. motor. There is 
no electrical connection • between the two units. Electrical power 
in the form of an alternating current is converted into mechanical 
power in the a.c. motor which drives the armature of the d.c. generator 
and again converts it into electrical power in the form of a direct 
current. The first cost of a motor-generator is such that its use is 
usually confined to large establishments handling quite a number of 
batteries, though motor generators are now made in much smaller 
sizes than formerly. 

A.C. Rectifiers. Where the amount of charging to be done 
does not warrant the investment in a motor-generator, a rectifier 
is usually employed. There are several makes of different types on 
the market: the chemical type, which employs lead and aluminum 
plates in an acid solution; the mercury-arc type, in which mercury 
is vaporized in a vacuum by the passage of the current; and others, 
in all of which the principle is the same. This consists in utilizing 
the current on but one part of the wave, so that the efficiency of 
these rectifiers ranges from 60 to 75 per cent. It is accordingly not 
good practice to employ them except in the smaller sizes. While 
the mercury-vapor rectifier is made for charging private vehicle 
batteries, the other types are ordinarily confined to sizes intended 
for charging small batteries. 

A recent addition to the list that is available for this purpose is 
the Tungar rectifier, made by the General Electric Company. The 
principle on which this works is the same, but the medium is a new 




Fig. 472. Interior View of Small Size G. E. Tungar Rectifier 
Courtesy of General Electric Company, Schenectady, New York 

(30 cells in all) may be charged at once. The batteries must be 
connected in series and then it is only necessary to turn the switch 
of the a.c. circuit. In case the alternating-current supply should fail, 
the battery cannot discharge through the rectifier, and the latter 


674 ELECTRICAL EQUIPMENT 


one. This is a bulb exhausted of air and filled with a special gas in 
which a heavy tungsten-wire filament is brought to incandescence 
by the passage of the alternating current. This filament is very 
short and thick, its diameter depending upon the capacity of the 

rectifier, and it is placed horizontally. It 
constitutes the cathode of the couple. 
Directly opposite it, but a short distance 
away, is the anode of graphite in the form 
of a button, the lower face of which is 
presented to the tungsten wire. It is made 
in three sizes, the smallest of which has a 
capacity of but 2 amperes and is designed 
for charging the batteries of small portable 
lamps, such as are used by miners; and 
for charging ignition, call bell, burglar 
alarm batteries, and the like. 

471. Front View of Large Size In the larger size, as shown in Fig. 

G. E. Tungar Rectifier ° ^ ^ ^ ^ 

471, the bulb is mounted in an iron case, 
on the face of which are mounted the switch for alternating cur¬ 
rent; an ammeter on the d.c. side, showing the charge received 
by the battery; and a dial switch for adjusting the voltage to 
the number of batteries to be charged. There is a compensator 
with 15 taps, and the current is adjustable by steps up to 6 amperes. 
Anything from a single three-cell battery up to ten of such units 





















ELECTRICAL EQUIPMENT 


675 





Fig. 473. Interior View of Large Size G.E. 
Tungar Rectifier 


will assume its task again automatically as soon as the current comes 
on. This is the 6-ampere 75-volt size. It is also made in a G-ampere 
15-volt size designed for the charging of a three- or six-cell starter 
battery in the home garage. Fig. 472 shows an interior view of this 
size, illustrating the position of 
the converting bulb, the compen¬ 
sator, the reactance coil, and the 
fuses, while Fig. 473 illustrates 
the 6-ampere 75-volt size, show¬ 
ing the panel instrument, i.e., 
switch, ammeter, and regulating 
handle, as well as the bulb and 
fuses. A closer view of the bulb 
itself is shown in Fig. 474. 

Care of Battery in Winter. 

There is a more or less general 
impression that special treatment 
must be given the storage battery 
during cold weather. This is probably owing to the fact that lack 
of attention makes itself apparent much more readily in winter than 
in summer because of the lower efficiency of the battery resulting 
from the lower temperature. The care necessary in winter does not 
vary in any respect from 
that which should be given 
in warm weather, except 
possibly that replacement of 
the water due to evapora¬ 
tion is not called for so 
often, but unless it is con- 
scientiouslv carried out, the 

4/ ' 

battery is apt to suffer to a 
greater extent. In speak- -pig. 474. 
ing of low temperatures, it 
must be borne in mind that this always refers to the temperature 
of the electrolyte of the battery, and not to that of the surrounding 
atmosphere. The latter may be considerably below freezing, whereas 
the liquid in the cells may be approaching 100° F. when the battery 
is under charge. 


Tungar Rectifying Bulb—the Heart of 
the Rectifier 










676 


ELECTRICAL EQUIPMENT 


Make the usual hydrometer and voltage tests, as described 
under the headings in question, and see that the battery is constantly 
kept more fully charged than would be necessary to render satisfactory 
service in warmer weather. This is important for two reasons: 
first, because of the greatly increased drain on the battery owing to 
the difficulty of starting the engine when cold; and second, because 
of the liability of the electrolyte to freeze if the battery is allowed 
to stand discharged in very cold weather. There is not the same 
excess supply of current available for charging the battery in winter 
as there is in summer, as the lights are in use during a much greater 
part of the time and not so much driving is likely to be done during 
the day. As the lamp load consumes almost the entire output of the 
generator in the average starting and lighting system, there is very 
little left for the battery when all the lamps are in use. The practice 
of turning on all the lights on the car—headlights, side lights spot 
light, and instrument lights—whether they are necessary or not, 
should be discouraged in winter, as it is likely to result in exhausting 
the battery. The instrument lights are usually in series with the 
tail light, and so cannot be dispensed with, but it is never necessary 
to have the headlights and side lights going at the same time, and 
this also applies to the spot light, which consumes almost as much 
current as one of the headlights and should be restricted to the use 
for which it is intended, i.e., reading signs by the roadside. 

Unless the lamp load is reduced, it may be necessary to increase 
the charging rate of the generator during the cold months, and this 
is not beneficial to the battery, as it may cause severe gassing and 
injury to the plates when continued too long. In case the car is 
not driven enough to keep the battery properly charged, it may be 
necessary to charge it from an outside source or, if the latter be not 
available, to run the engine with the car idle just for this purpose. 
Care must be taken to prevent any danger of freezing, and the best 
method of doing this is to keep the battery fully charged, as when in 
this condition it will freeze only at very low temperatures. The 
more nearly discharged a battery is, the higher the temperature at 
which it will freeze, and freezing will ruin the cells, regardless of 
whether it happens to crack the jars or not. 

Why Starting Is Harder in Cold Weather. The electric starting 
and lighting system, or rather the storage battery, which is its main- 



ELECTRICAL EQUIPMENT 


677 


stay, is much more severely taxed in winter than in summer for the 
following four reasons: ^ 

(1) The efficiency of the storage battery decreases with a 
decrease in temperature, because the action of the storage battery is 
chemical, and chemical action is dependent upon heat and, therefore, 
always decreases as the temperature decreases. 

(2) The lower the temperature the stiffer the lubricating oil, 
which gums the moving parts together, adding a very considerable 
load to the ordinary amount of inertia which the starting motor 
must overcome and likewise adding to the difficulty of turning the 
engine past compression. 

(3) Gasoline will not vaporize readily at a low temperature, so 
that it is necessary to turn the engine over a great many revolutions 
before the cylinders become sufficiently warmed from the friction 
and the repeated compression to create an explosive mixture. The 
better the mixture the more readily it will fire, and consequently 
a greater heat value is required in the spark to ignite it where the 
mixture is poor or only partly vaporized. Anything that reduces 
the efficiency of the storage battery likewise reduces the heat value 
of the ignition spark. 

(4) Low heat value of the spark often makes it difficult to 
start an engine when cold. This lack of heat in the spark is caused 
by a partially discharged battery as well as the lower efficiency of 
the battery caused by the cold weather; also by the necessity for 
repeated operation of the starting motor, whereby the voltage of the 
battery is temporarily cut down. 

Intermittent use of the starting motor with a brief period between 
attempts will frequently result in starting a cold engine where 
continued operation of the starting motor will only result in exhausting 
the battery to no purpose. The longer the starting motor is operated 
continuously the lower the voltage of the battery becomes, with a 
corresponding drop in the heat value of the ignition spark. Cranking 
intermittently a number of times has practically as great an effect 
in warming the cylinders and generating an explosive mixture as 
running for the same period (actual operating time in each case), 
while the brief periods of rest permit the battery to restore its normal 
voltage, which increases the heat value of the spark and causes the 
engine to fire. Both the storage battery and the remaining essentials 


G78 


lELECTRICAL EQUIPMENT 


of the starting and lighting system are designed to give satisfactory 
service in cold weather, but as a very low temperature brings about 
conditions representing the maximum for which the system is designed, 
more skillful handling is necessary in winter than in summer to obtain 
equally good results. 

To Test Rate of Discharge. If the battery terminals are 
removable, take off either the positive or the negative terminal, 
and connect the shunt of the ammeter to the terminal post and to 
the cable which has been removed, binding or wiring it tightly in 
place to insure good contact. Where the battery terminals are 
not easily removable, insert the shunt in the first joint in the line. 



Fig. 475. Setup for Testing Rate of Discharge of Small Storage 

Battery 

Courtesy of Prest-O-Lite Company, Indianapolis, Indiana 


as shown in the illustration. Fig. 475. Then connect the ammeter 
terminals to the shunt. In case the instrument shows a reverse 
reading, reverse the connections to the shunt. When the ammeter 
is connected to test for discharge, the starter must never be used 
unless the 300-ampere shunt is in circuit, as otherwise the instrument 
is likely to be damaged. If a shunt of smaller capacity or a self- 
contained ammeter, i.e., one designed to be connected directly in 
the line is employed, and it is necessary to start the engine, either 
crank by hand or disconnect the ammeter before using the starting 
motor. 









ELECTRICAL EQUIPMENT 


679 


When the ammeter is connected to show the discharge and no 
lights are on, the engine being idle, no current is being used for any 
purpose, and the pointer of the ammeter should remain at zero. If 
any flow of current (discharge) is indicated, it shows that there is 
a ground or a short-circuit (a leak) somewhere in the system. In 
such a case, apply the usual tests described under the appropriate 
headings for locating grounds and short-circuits. 

With the ammeter connected up as shown in the illustration, 
the discharge rate of the battery under the various loads it is called 
upon to carry may be checked up, and, if it proves to be excessive 
in any case, the trouble may be remedied. For example, with the 
300-ampere shunt in the line, the amount of energy consumed by 
the starting motor may be checked. Without knowing how much 
current a certain make of starting motor should consume in turning 
over a given type of engine, it will naturally be impossible to make 
any intelligent comparisons with the result of the tests. This infor¬ 
mation, however, is readily obtainable from the manufacturer of 
the starting system, and it will be found advantageous to obtain 
details of this nature covering the various systems in general use in 
your locality, as it will enable you to make these tests valuable in 
correcting faults. While the starting loads imposed on the electric 
motor by different engines will vary greatly, the general nature of 
the load will be practically the same in all cases. When the starter 
switch is closed, there will be an excessive discharge rate from the 
battery for a few seconds, the discharge falling off very rapidly as 
the inertia of the engine is overcome and it begins to turn over, 
with a still greater drop to a comparatively small discharge the 
moment it takes up its cycle and begins to run under its own power. 

Before undertaking such tests, see that the battery is in good 
condition and fully charged. Make several tests. Note in each 
case whether the maximum discharge at the moment of closing the 
switch exceeds the maximum called for by the maker of the starting 
system. If a great deal more current is necessary to turn the engine 
over than should be the case, it is an indication either that the 
starting motor is in need of attention or that the engine itself is 
unusually stiff. Atmospheric conditions will naturally have a decided 
effect on the result of such tests, as an engine that has stood overnight 
in a cold garage will be gummed up with thick lubricating oil and 


680 


ELECTRICAL EQUIPMENT 


will require more power to move it at first than if it had been running 
only a few minutes before. As a general rule, more power will 
always be needed in winter than in summer, unless the tests are 
carried out in a well-heated garage. The condition of the engine 
itself will also have an important bearing on the significance of the 
tests, as, if the engine has been overhauled recently, its main bearings 
may have been tightened up to a point where the engine as a whole 
is very stiff. 

Note also whether the discharge rate falls off as quickly as it 
should when the engine begins to turn over rapidly. If it does not, 
this also is an indication of tight bearings, gummed lubricating oil, 
or similar causes, rendering the engine harder to turn over. In 
the case of a cold engine, stiffness due to the lubricating oil may be 
remedied by running it for ten or fifteen minutes, and a subsequent 
test should then agree with the manufacturer’s rating. Where the 
discharge rate does not drop to a nominal amperage within a few 
seconds from the time of closing the switch, it is simply an indication 
that the essentials of the engine are not in the best of working order. 
The carburetor may not be working properly, or the ignition may 
be sluggish. 

In case the discharge rate is very much less than that called for 
by the manufacturer for that particular engine, it is an indication 
that the starting system itself is not in the best condition. Poor 
connections, worn brushes, loose brush springs, a dirty switch, or 
some similar cause is greatly increasing the resistance in the starting 
circuit, thus cutting down materially the amount of current that the 
battery can force through it. In such circumstances, the discharge 
may not reach so high a rate as that called for by the manufacturer, 
but to effect a start, even with the engine in normally good condition, 
a high rate will have to be continued longer, to the correspondingly 
greater detriment of the battery. In other words, a great deal more 
current must be drawn from the battery each time the engine is 
started. Thus, testing the rate of discharge may be made to serve 
as an indication of the condition of both the starting system and 
the engine itself. Should it be necessary to make more than eight 
or ten starts to determine definitely the cause of any variation between 
the discharge rates shown and those that should be indicated, with 
everything in normally good condition, the battery should be fully 


ELECTRICAL EQUIPMENT 


681 


recharged before proceeding any further, as using it for this purpose 
when almost exhausted is very likely to damage it. Tests of this 
kind show also whether the efficiency of the battery has fallen off 
substantially or not, as indicated by its condition after making 
several starts in succession. When this has been done, the battery 
may be tested with the voltmeter and hydrometer to ascertain how 
far it has been discharged. The fact that after having been in service 
for some time a starting system will not start the engine so many 
times without exhausting the battery as it would when new may 
be due either to a loss of efficiency in the battery or to the poor 
condition of the other essentials of the system. In the majority of 
cases, however, it will be due to the condition of the battery. 

By substituting the 30-ampere shunt for the 300-ampere, the 
load put on the battery by the lights when switched on in various 
combinations may be checked and compared with the manufacturer’s 
ratings. Where the discharge rate for the lights is less than it should 
be, it may be due to the use of bulbs which have seen a great deal 
of service, the resistance of the filaments increasing with age, or 
other causes which place more resistance in the circuit, such as poor 
connections, loose or dirty switches, and the like. Tests may also 
be made of the ignition system where the battery is called upon to 
supply current to a distributor and coil by putting the 3-ampere 
shunt in the circuit. The amount of current required by the ignition 
system is very small when everything is in normal working order, 
usually not more than 1| to 2 amperes. This also can be obtained 
definitely from the maker of the apparatus. Any great increase 
in the amount of current necessary would usually indicate arcing at 
the contact points, which should prove to be in poor condition; a 
subnormal discharge would signify a great increase in the resistance 
as in the foregoing cases, and should be evidenced by poor ignition 
service. 

To Test Rate of Charge. To determine the rate at which the 
battery is being charged (the small dash ammeters are only approxi¬ 
mately accurate), reverse the ammeter connections and start the 
engine by hand. If the car is equipped with a straight 6- or 12-volt 
system and a dash ammeter is used, see that its reading agrees 
approximately with the portable ammeter. Should the variation 
be small, advise the owner so that he may correct his readings 


682 


ELECTRICAL EQUIPMENT 


accordingly when noting the instrument on the road. In case it is 
very large, the dash ammeter itself should be adjusted, which can 
frequently be done merely by bending the pointer. 

With the engine running fast enough to give the maximum 
charging rate, which is indicated by the fact that the ammeter 
needle stops rising, check the charging rate shown on the portable 
ammeter, bearing the following in mind: In the majority of cars, 
the generator is regulated to charge the battery at from 10 to 15 
amperes. Some are designed to charge at as low a rate as 7 amperes. 
Lhiless the proper charging rate is definitely known, whatever 
maximum the portable ammeter shows may usually be assumed to 
be correct. Where the rate is less than 7 amperes it may generally 
be taken for granted, however, that the battery is undercharging, 
and the various tests, described in detail under appropriate headings, 
may be applied to locate the trouble either in the generator or in 
the automatic cut-out. This applies where the charging rate is too 
high as well as where it is too low. 

The charging rates mentioned above naturally apply only to a 
6-volt battery, or to a battery having a greater number of cells, 
which is connected in series multiple so as to charge at 6 volts. 
In the case of a six-cell battery permanently connected in series so 
that it both charges and discharges at 12 volts, the above figures 
must be cut in half. Twelve-cell batteries are employed in some 
cases, but the total voltage of the battery is used only for starting, 
the cells being divided into four groups in series multiple so that 
each group of three cells charges at 6 volts. 

With the generator charging at 10 to 15 amperes, turn on all 
the lights. If more current is being drawn from the battery than 
is being supplied by the generator, this will be indicated by the 
ammeter showing a reverse reading or discharge. It signifies 
that there is a short-circuit in the lighting switch or the lamps, or 
in the wiring between the switch and the lamps, or that additional 
lights, other than those furnished originally with the system, have 
been added, or larger candle-power bulbs substituted, thus placing 
too great a demand on the battery. 

If the system has been out of adjustment for any length of 
time, it is quite likely that the battery will shortly need repairs or 
replacement, because charging at an excessive rate causes the plates 


ELECTRICAL EQUIPMENT 


683 


to buckle and break through the separators, forming an internal 
short-circuit, while charging at too low a rate causes a constantly 
discharged condition of the battery, due to more current being 
normally called for than is put in. This results in injurious sulphating 
of the plates. 

In case additional equipment has been added, the entire 
equipment should be turned pn, and the total current required should 
be noted when making discharge-rate tests. Where the generator 
cannot supply sufficient current to permit the battery to take care 
of this extra equipment, the battery should be charged from an 
outside source at regular intervals. It is poor practiee to increase 



Fiff 470 Setup for Twelve-Volt Battery Wired to Charge and Discharge 
through Starting Motor at Twelve Volts and through 
Lamps at Six Volts 


the charging rate of the generator, as it is likely to injure the battery 
through overheating. Where it is necessary to have a higher charging 
rate than that originally called for by the system, it is preferable to 
substitute a larger battery. The charging rate of the generator may 
then be safely increased in accordance with the demand. 

In cold weather, it may be necessary to slightly increase the 
charging rate of the generator in order to compensate for the extra 
current the battery is called upon to supply. 1 his is owing, not only 
to the fact that there is a much greater demand on the starting 
svstem in cold weather, but also to the fact that the battery is less 
efficient under winter conditions of operation, 

































684 


ELECTRICAL EQUIPMENT 


Connections for Two-Voltage Batteries. Where the battery is of 
either three or six cells, all connected permanently in series, the 
foregoing suggestions for connecting the testing instruments apply. 
They must be varied, however, where tests are to be made of batteries 
connected in series multiple, which may be termed two-voltage 
batteries since they supply current at one voltage for lighting and 
at another for starting. In Fig. 476 is shown a battery of this type 
which is connected so as to charge and discharge through the starting 
motor at 12 volts, but which discharges at 6 volts to supply the 
lamps through a neutral lead in the center of the battery. The 
sketch indicates where to connect the ammeter shunt on charge at 



Fig. 477. Twelve-Volt Battery Connected Up to Make Two 6-Volt 

Batteries in Parallel 


12 volts and on discharge at 6 volts. When testing the starting-motor 
discharge, it would be connected for 12 volts. 

Test the 12-volt circuit with the engine running to get the 
charging rate; stop the engine, reverse the ammeter terminals and 
see whether there is any discharge indicating a short-circuit. Also 
test the discharge rate on the 6-volt circuit with the lights turned off 
and again with all lights on. These tests should show whether or 
not there is a short-circuit in the system. Before attempting to 
test the discharge rate of the starting motor, be certain that the 
300-ampere shunt is in the circuit. A 12-volt battery will discharge 
only about half the current necessary to start the engine with a 
6-volt battery, but no shunt smaller than the 300-ampere size can 
be depended upon to carry the load safely and protect the instrument. 


















ELECTRICAL EQUIPMENT 


685 


Fig. 477 shows a 12-volt battery connected up in such a manner 
that it is practically two 6-volt batteries in parallel. The battery 
is charged at 6 volts, and both the lights and horn are supplied with 
current at this voltage, but the discharge through the starting motor 
is at 12 volts. Note the two positive cables leading to the center 
of the battery. To test the charging rate, the ammeter shunt should 
be connected first in one of these cables and then in the other, and 
the two readings added together to obtain the charging rate for the 
entire battery. The same locations for the shunt, and the same 
method of adding the readings also apply on discharge. Ammeter 
readings in the connections shown will indicate whether or not 
there are any short-circuits, except, of course, in the starting-motor 
cable. 

Voltage Tests. An equally important instrument for the testing 
of the storage battery is the voltmeter. It is chiefly useful in showing 
whether a cell is short-circuited or otherwise in bad condition. Under 
some conditions, it indicates when the battery is practically 
discharged, but, like the hydrometer, it must not be relied upon 
alone. It should be used in conjunction with the hydrometer readings 
to insure accuracy. Since a variation as low as .1 (one-tenth) of a 
volt makes considerable difference in what the reading indicates as 
to the condition of the battery, it will be apparent that a cheap 
and inaccurate voltmeter is likely to be misleading rather than 
helpful. For garage use, a good reliable instrument with several 
connections for giving a variable range of readings should be employed. 
Instructions furnished with the instrument give in detail the method 
of using the various connections, and these instructions should be 
followed closely, as otherwise the voltmeter is likely to be damaged. 
For example, on the 3-volt scale only one cell should be tested. 
Attempting to test any more is likely to burn out the 3-volt coil 
in the meter. The total voltage of the number of cells tested must 
never exceed the reading of the particular scale being used at the 
time, as otherwise the instrument will be ruined. 

Always make certain that the place on the connector selected 
for the contact of the testing point is clean and bright and that 
the contact is firm, as otherwise the reading will be misleading, 
since the increased resistance of a poor contact will cut down the 
voltage. The positive terminal of the voltmeter must be brought 


686 


ELECTRICAL EQUIPMENT 


in contact with the positive terminal of the battery, and the negative 
terminal of the voltmeter with the negative terminal of the battery. 
If the markings of the cell terminals are indistinct, the proper terminals 
may be determined by connecting the voltmeter across any one cell. 
Should the pointer not give any voltage reading, butting up against 
the stop at the left instead, the connections are wrong and should 
be reversed; if the instrument shows a reading for one cell, the positive 
terminal of the voltmeter is in contact with the positive of the cell. 
This test can be made with a voltmeter without any risk of short- 
circuiting the cell, since the voltmeter is wound to a high resistance 
and will pass very little current. This is not the case with an ammeter. 



€-VQLT BATTK&Y 

Fig. 478. Proper Setup for Testing Voltage of Batteries 


however, as connecting such an instrument directly across the 
terminals of the battery will immediately burn out the ammeter. 

Inasmuch as any cell, when idle, will show approximately .2 
volts, regardless of whether it is fully charged or not, voltage readings 
taken when the battery is on open circuit, i.e., neither charging 
nor discharging, are practically valueless, except when a cell is out 
of order. Therefore, a load, such as switching on the lamps, should 
be put on the battery before making voltage tests. With the lights 
on, connect the voltmeter as explained above and test the individual 
cells. Fig. 478 (Prest-O-Lite). If the battery is in good condition, 
the voltage readings after the load has been on for about five minutes 
will be but slightly lower (about one-tenth of a volt) than if the battery 
w^re on open circuit. If any of the cells are completely discharged^ 















ELECTRICAL EQUIPMENT 


687 


the voltage of these cells will drop rapidly when the load is first 
put on and, sometimes when a cell is out of order, even show reverse 
readings. Where the battery is nearly discharged, the voltage of 
each cell will be considerably lower than if the battery were on open 
circuit after the load has been on for five minutes. In the case of an 
electric-vehicle battery, the lights alone would not provide sufficient 
load for making an accurate test, so that one of the rear wheels may 
be jacked up and the brake set lightly until the ammeter on the 
dash of the car shows 50 to 70 per cent of the usual normal reading. 
To do this, start the motor on first speed with the brakes loose, 
and apply the brakes slowly until the desired load is shown by 
the ammeter reading. Never, under any circumstances, attempt to 
start with the brakes locked or on hard, as both the battery and the 
motor will be damaged. In the case of a starting-system battery, 
the lights alone are sufficient load, as they consume about 10 amperes. 

To distinguish the difference between cells that are merely 
discharged and those that are out of order, put the battery on charge 
(crank the engine by hand in the case of a starter battery) and test 
again with the voltmeter. If the voltage does not rise to approxi¬ 
mately 2 volts per cell within a short time, it is evidence of internal 
trouble which can be remedied only by dismantling the cell. 

Teviperature Variations in Voltage. It must be considered, in 
making voltage tests, that the voltage of a cold battery rises slightly 
above normal on discharge. The reverse is true of a really warm 
battery in hot weather, i.e., it will be slightly less than normal on 
charge and higher than normal on discharge. As explained in 
connection with hydrometer tests of the electrolyte, the normal 
temperature of the electrolyte may be regarded as 70° F., but this 
refers only to the temperature of the liquid itself as shown by a 
battery thermometer, and not to the temperature of the surrounding 
air. For the purposes of simple tests for condition, voltage readings 
on discharge are preferable, as variations in readings on charge mean 
little except to one experienced in the handling of storage batteries. 

Joint Hydrometer and Voltmeter Tests. In making any of the 
joint tests described below, it is important to take into consideration 
the following four points: 

(1) The effect of temperature on both voltage and hydrometer 
readings. 


088 


ELECTRICAL EQUIPMENT 


(2) Voltage readings should only be taken with the battery 
discharging, the load being proportioned to the size of the battery, 
as voltage readings on an idle battery in good condition indicate 
little or nothing. 

(3) In the case of a starter battery, never attempt to use the 
starting motor to supply a discharge load for the battery, because 
the discharge rate of the battery while the starter is being used is so 
heavy that even in a fully charged battery in good condition it 
will cause the voltage to drop rapidly. 

(4) The voltage of the charging current will cause the voltage 
of a battery in good condition to rise ,to normal or above the moment 
it is placed on charge, so that readings taken under such conditions 
are not a good indication of the battery’s condition. 

In any battery which is in good condition, the voltage of each 
cell at a normally low discharge rate (20 to 30 amperes for a vehicle 
battery or 5 to 10 amperes for a starting-system battery) will remain 
between 2.1 and 1.9 volts per cell until it begins to approach the 
discharged condition. A voltage of less than 1.9 volts per cell indicates 
either that the battery is nearly discharged or that it is in bad 
condition. The same state is also indicated when the voltage drops 
rapidly after the load has been on a few minutes. The joint hydrome¬ 
ter and voltmeter tests given below will be found to cover the 
majority of cases met with in actual practice. 

(1) A voltage of 2 to 2.2 per cell with a hydrometer reading 
of 1.275 to 1.300 indicates that the battery is fully charged and in 
good condition. 

(2) A voltage reading of less than 1.9 per cell with a hydrometer 
reading of 1.200 or less indicates that the battery is almost completely 
discharged. 

(3) A voltage of 1.9 or less per cell with a hydrometer reading 
or 1.220 or more indicates that excess acid has been added. Under 
these conditions, lights will burn dimly, although the hydrometer 
reading alone indicates the battery to be more than half charged. 

(4) Regardless of voltage—high, low or normal—any hydro¬ 
meter reading of over 1.300 indicates that an excessive amount 
of acid has been added. 

(5) Where a low voltage reading is found, as mentioned in 
cases 2 and 3, to determine whether the battery is in bad order or 


ELECTRICAL EQUIPMENT 


689 


merely discharged, stop the discharge by switching off the load, and 
put the battery on charge (crank the engine by hand in the case of 
a starter battery) and note whether the voltage of each cell promptly 
rises to 2 volts or more. If not, the cell is probably short-circuited 
or otherwise in bad condition.* 

Cleaning Repair Parts. The advent of electric starting and 
lighting systems has added appreciably to the amount of attention 
required by machines in the garage, particularly as this essential 
is a part of the car about which its owner generally knows little. In 
fact, it is not overstating it to say that fully 25 per cent of all the 
repair work now carried on in the garage has for its object the keeping 


5av\^ Dust iSoJc 


Fig. 479. Layout for Battery Cleaning Outfit 

of the electrical equipment of the car in good operating condition. 
Where many cars are cared for and repairs to their electric systems 
are made as far as possible right in the garage, it will be found 
advisable to install a method for cleaning parts. Owing to the accumu¬ 
lations of dirt and grease that parts carry after having been in service 
for a year or more, cleaning them thoroughly before making any 
repairs makes it possible to detect defects which might otherwise 
pass unnoticed. The following instructions are reprinted through 
the courtesy of the makers of the Delco apparatus, and they strongly 
recommend that the solutions mentioned be used in the exact manner 



Hot Water 


Hot Water 


Cauotic5o(k 
Or Polash 
Solution 
Hot 

Tank No.} 


Tank. No. £ 


TankNo.3 


* From instructions issued by the Prest-O-Lite Company, Indianapolis, Indiana. 

































090 


ELECTRICAL EQUIPMENT 


directed, as they are the result of several years’ experience in this 
work, and considerable care has been used in checking them. The 
sizes of the tanks given are merely indicative of what a very large 
repair shop would require and are comparative only. They will 
naturally vary with the amount of work to be done. 

Cleaning Outfit. The cleaning outfit should consist of three 
sheet-steel tanks. Fig. 479, of suitable size (35 gallons for a large 
shop) mounted so that their contents may be kept heated to the 
desired temperature, three stone jars of approximately 15 gallons 
capacity, and a sawdust box. Two of the steel tanks should be 
equipped with overflow pipes so that they can be kept about two- 
thirds full at all times. These are tanks No. 1 and No. 2. They are 
used for clear hot water for rinsing parts after they have been cleaned. 
The third tank does not require a drain nor an overflow pipe and is 
used for the potash or caustic soda solution. This can be used for 
a long time without changing by simply adding a small amount of 
soda as the solution weakens. All three tanks are maintained at a 
temperature of 180° to 212° F., or approximately the boiling point. 

The three jars mentioned are used for the acid solutions and are 
referred to as jars No. 1, No. 2, and No. 3. A wood tank large enough 
to hold the three jars and divided into two compartments, as shown 
in Fig. 479, should be provided. This is important, as the parts 
cannot be rinsed in the same cold water after being immersed in the 
different acid solutions. The solutions recommended are in tanks 
1 and 2, clear hot water; tank 3, a solution consisting of one pound 
of caustic soda per gallon of water. Jar No. 1 is filled with a solution 
consisting of four gallons of nitric acid, one gallon of water, and six 
gallons of sulphuric acid. The water is placed in the jar first, the 
nitric acid is added slowly, and the sulphuric acid is poured in last. 

• This order must be strictly followed, as it is dangerous to mix a 
solution of these acids in any other manner. In jar No. 2, the solution 
is one gallon of hydrochloric acid to three gallons of water, while 
jar No. 3 contains a solution of one-half pound of cyanide to a gallon 
of water. Tank No. 2 should be used only for parts which have 
been in the potash solution and for no other purpose. Tank No. 1 
is for general rinsing purposes. 

Method of Cleaning Parts. Various metals are cleaned as follows: 
Steel is boiled in the potash solution until the dirt is removed, which 


ELECTRICAL EQUIPMENT 


GOl 


should require only a few minutes. The steel part is then rinsed 
in tank No. 2 and dried in sawdust. Vast iron parts are boiled 
in the potash solution to remove dirt, rinsed in tank No. 2, dipped 
in the acid solution in jar No. 1, rinsed thoroughly in cold clear 
water, dipped in the cyanide solution, rinsed again in cold 
clear water, then rinsed in tank No. 1 and dried in sawdust. Copper 
can be cleaned in the same manner. Polished aluminum should 
first be thoroughly washed in gasoline, rinsed in tank No. 1, dipped 
in the acid solution in jar No. 1, rinsed thoroughly in cold clear 
water, rinsed in tank No. 1, and dried in sawdust. Plain aluminum, 
unpolished, should be dipped in the potash solution, rinsed in tank 
No. 2, dipped for a few seconds in the acid solution, rinsed in 
tank No. 2, dipped for a few seconds in the acid solution in Jar 
No. 1, rinsed in cold water, then rinsed in tank No. 1, and dried in 
sawdust. 

It will be noticed that when aluminum is put into the potash 
solution the metal is attacked and eaten away rapidly, so that 
polished parts of this metal should not be put into this solution, 
and any aluminum parts should not be left in for a moment longer 
than necessary. Where the parts are covered with caked deposits 
of hard grease, they should first be washed in gasoline. Aluminum 
parts should never be put into the potash solution unless they can 
be put through the acid immediately after, as the acid dip neutralizes 
the effect of the potash solution. Parts should only be held in the 
acid for a few seconds. Paint should first be removed with a good 
paint or varnish remover unless it is present in very small quantity, 
and unless the aluminum parts are to go through the potash solution. 
Enameled work should be washed with soap and water, dried 
thoroughly, and then polished with a cloth dampened with a good 
oil, such as Three-in-One. .These cleaning methods apply only 
to solid parts and should never be employed on any plated pieces, 
as the caustic and acid would immediately strip off the plating. 
Such parts can be cleaned only in gasoline. It will be apparent, 
however, that cleaning in this manner will be found advantageous 
for many parts of the car that have to be repaired other than those 
of the electric equipment, and, in view of the increasing cost of 
gasoline, will be found much more economical as well as much more 
thorough. 



TYPICAL BOSCH-RUSHMORE STARTING MOTOR 

Courtesy of Bosch Magneto Company, New York City 



BOSCH MAGNETO INSTALLATION ON 1916 HUPMOBILE 

Courtesy of Bosch Magneto Company, New York City 













ELECTRICAL EQUIPMENT FOR 

GASOLINE CARS 

PART IX 


ELECTRIC STARTING AND LIGHTING 
SY STEMS —(Continued) 


SUMMARY OF INSTRUCTIONS ON ELECTRIC 
STARTING AND LIGHTING 

It will be apparent from the foregoing description of the various 
systems that while the majority differ more or less in detail all are 
based on a comparatively small number of well-defined principles, 
and that once these are mastered their application in any system 
under consideration will be clear. To avoid unnecessary duplication 
in the instructions covering points that are common to all, general 
instructions have been given only in connection with one or two 
systems, and it will be understood that descriptions of the methods 
of locating short-circuits or grounds, of caring for brushes and com¬ 
mutator, and of testing with a portable lamp or with the volt-ammeter 
are equally applicable to all. The instructions given with other 
systems accordingly are limited to special references to the details 
of installation that will make it easier to locate faults in that par¬ 
ticular system. 

In order to bring the two together in such form that the par¬ 
ticular information desired may be found instantly, a summary 
of all the instructions given in the preceding sections is outlined here 
in questions and answers. 

GENERATORS 

Types and Requirements 

Q. How many types of generators are used in starting and 
lighting service on the automobile? 

A. Practically all are of one type, i.e., compound-wound, but 
this is subdivided into other types, such as differential compound- 




G04 


ELECTRICAL EQUIPMENT 


wound, cumulative compound-wound, and the like, that is, all 
lighting generators have a shunt and a series winding on their fields, 
but the relation of these windings to one another differs, depending 
upon the characteristics of the remainder of the system. 

Q. What is a differential compound=wound generator? 

A. One in which the series winding is reversed, i.e., wound in a 
direction opposite to that of the shunt winding so that its exciting 
eft'ect on the field magnets opposes that of the shunt winding. The 
series winding is then termed a bucking coil because it bucks, 
or opposes, the exciting effect of the shunt winding on the field mag¬ 
nets as the speed increases. The series winding in this case is used 
simply for regulating the generator output. 

Q. What is a cumulative compound=wound generator? 

A. One in which the exciting effect of the series coil is added to 
that of the shunt coil, the series coil in this case having no connection 
with the regulation of the generator output. 

Q. As one of the chief requirements of an efficiently operating 
system is the control of the generator output under widely varying 
speeds, how is a generator of the cumulative compound=wound type 
employed on the automobile? 

A. The series winding is in practically an independent circuit 

s 

in connection with the lamps of the car so that its exciting effect is not 
added to the field magnets except when the lights are switched on. 
This automatically increases the generator output in accordance with 
the number of lights turned on so that the lights have no effect on the 
battery charging rate, which remains the same whether the lights are 
on or off. An external regulator is employed to control the battery¬ 
charging rate. 

Q. How does the generator differ from the motor? 

A. Its essentials are all the same, i.e., it has a wound armature 
revolving in a magnetic field, commutator, brushes, etc., exactly the 
same as the generator. 

Q. This being the case, why are the two not interchangeable? 

A. To a certain extent they are, that is, when a current is sent 
through the generator from an outside source, it becomes motorized 
and will run as a motor. But the two are far from being interchange¬ 
able on the automobile, owing to the widely differing requirements for 
which they are designed. The generator is wound to produce a cur- 


ELECTRICAL EQUIPMENT 


695 


rent seldom exceeding a value of 20 amperes while being driven over a 
wide range of speeds, and it is in constant operation. The starting 
motor, on the other hand, is designed to utilize an extremely heavy 
current, ranging up to 300 amperes or mo*re at the moment of starting 
and is only used for very short periods. 

Q. How are these widely varying requirements reconciled in 
the single=unit type, in which both the generator and the motor are 
combined in one machine? 

A. The machine is practically two units in one, i.e., there are 
two totally different windings on the same magnet cores, a fine wind¬ 
ing with shunt fields for the generator, and a very heavy simple series 
winding for the motor end. In some cases, as in the Delco, the differ¬ 
ent windings on the armature are brought out to independent commu¬ 
tators. While combined on one set of magnet cores, there is no 
connection whatever between the two windings in such a machine, so 
that when operating as a generator the motor windings are dead, and 
the reverse is true when being used as a starting motor. 

Q. What are the characteristics of the single=unit type of 
machine which is simply placed in circuit with the battery by a hand= 
operated switch when starting and left in that relation as long as the 
engine is running? 

A. This is a variable-potential type in which the relation that it 
bears to the battery and to the engine is entirely dependent upon the 
speed of the engine, that is, the speed at which the machine is driven. 
When the switch is closed, current from the battery operates the 
machine as a starting motor; as soon as the engine starts and attains 
a certain speed, the voltage of the machine overcomes that of the 
battery, the direction of current flow is reversed, and the battery begins 
to charge. Whenever the driving speed falls below a certain point, 
there is another reversal, and the generator once more becomes a motor 
until the engine speed increases. 

Loss of Capacity 

Q. What are the chief causes for the falling off in output of 
the generator? 

A. In about the order of the frequency of their occurrence, 
these are as follows: dirty or worn commutator; worn brushes making 
poor contact; dirty or loose connections causing extra resistance 


696 


ELECTRICAL EQUIPMENT 


at generator, regulator, cut-out, ground, or battery terminals; 
failure of cut-out to operate at proper voltage; worn or pitted con¬ 
tacts in regulator or cut-out; loose connections at brush holders; 
short-circuited coils in the armature; some of the armature-coil 
connections broken away from the commutator; short-circuited 
bars in the commutator. 

Q. How can the generator output be tested? 

A. The simplest method is to switch on all the lamps with 
the engine idle. Start the engine and speed up to equivalent of 
15 miles per hour. The lights should brighten very perceptibly, 
the test being made indoors in the daytime with the lights directed 
against a dark wall, or preferably at night. A more accurate test 
can be made with the portable volt-ammeter, using the 30-ampere 
shunt. Most generators have an average current output of 10 to 
12 amperes, but the normal output as given by the maker should 
be checked before making the test. Generators having a constant- 
voltage control will show a greatly increased output if the battery 
charge is low, running up to 20 amperes or over. On such machines, 
the condition of the battery should be checked either with the 
hydrometer or with the voltmeter before making the test. The 
charging current should be 10 to 12 amperes with a fully charged 
battery, and more in proportion when only partly charged. 

Q. What other simple method is there of determining quickly 
whether the generator is producing its normal output or not? 

A. On generators having an accessibly located field fuse (there 
are several makes) lift this fuse out and, with the engine running 
at a speed equivalent to 10 miles per hour or more, touch the fuse 
terminals lightly to the clips. If the machine is generating properly, 
there will be a bright hot spark. Should no spark appear, replace 
the fuse and bridge the terminals with a pair of pliers by touching the 
jaws to the fuse clips; if a spark appears, the fuse has blown. Before 
replacing with a new fuse, find the short-circuit or other cause. 

Q. Granting that the fuse has not blown, that the cut=out, 
regulator, and wiring are all in good condition, and still the gen= 
erator does not produce any current, what is likely to be the cause? 

A. One of the brushes may not be touching the commutator, 
a brush connection may have broken, or carbon dust may have short- 
circuited the armature or field windings. Test for short-circuits. 


ELECTRICAL EQUIPMENT 


697 


Q. If the machine is generating current, and the auxiliary 
devices and wiring are in good condition, but the battery does not 
charge, what is the cause? 

A. Short-circuit in the battery due to active material having 
been forced out of the plates, or accumulation of sediment touching 
plates at their lower ends. (See Battery Instructions.) 

Q. Is the regulator ever responsible for a falling off in the 
current or for generation of excessive current? 

A. Yes. Any irregularity in the operation of the regulator 
will affect the output of the generator. 

Q. How can this be overcome? 

A. This will depend upon the type of regulation employed 
(see Regulation). Where the method of regulation is inherent, 
i.e., forming part of the construction of the generator itself, such 
as the third-brush method, or a bucking coil, it may be remedied 
by cleaning and seating the brush properly or by testing the bucking- 
coil winding to see if its connections are tight and clean, or if it is 
short-circuited (see Windings). If cleaning and sanding-in the 
brush do not cause the generator to produce its normal output, the 
brush itself may be adjusted by shifting its location. Moving it 
backward or against the direction of rotation of the commutator 
will reduce the output; moving it forward or in the direction of 
rotation will increase the output. This refers specifically to the 
Delco regulation already described. To adjust properly, the port¬ 
able ammeter should be put in circuit, and the effect on the reading 
noted as the brush is moved, clamping it back in place when the 
proper point is found. The brush should then be sanded-in to the 
commutator, as it will not have a good bearing if its original location 
has been disturbed. 

Methods of Regulation 

Q. Why is it necessary to control the output of the generator? 

A. As explained in the section on electric generators, the 
amount of current produced depends upon the excitation of the fields, 
and the faster the armature revolves before the pole faces of the field 
magnets, the greater the amount of current that is sent through the 
windings of the magnets. As the speed of the automobile engine 
varies between such extremely wide limits, it will readily be seen that 


698 


ELECTRICAL EQUIPMENT 


it may rise to a point where this increase in the field excitation will 
cause so much current to be generated that the armature windings 
will be literally burned up. This happened very frequently in the 
early attempts to produce a lighting dynamo for automobile service. 
Regardless of how fast the generator may be driven, it is essential that 
its current output does not exceed a certain safe limit. 

Q. What is the usual safe limit in the majority of generators? 

A. IMost automobile lighting-system generators are designed to 
produce 10 to 15 amperes at a normal speed, i.e., sufficient to light all 
the lamps and still provide a slight excess for charging the battery. 
No matter how fast its armature revolves, it must not exceed this by 
more than ten to twenty-five per cent, as a rule, this being well within 
its factor of safety. In some instances, where a voltage system of 
regulation is employed, the output of the generator depends upon the 
condition of charge of the battery. If the battery is practically 
discharged, the generator will charge the battery at a rate of twenty 
amperes or over. As the charge proceeds, the battery voltage 
increases and the resistance is increased correspondingly, thus cutting 
down the amount of current that the generator can force into the 
battery. 

Q. How is the current generated kept from exceeding this safe 
limit? 

A. Mechanical methods were employed at first, a centrifugal 
governor being used to operate a slipping clutch. The generator 
was driven through this clutch, and the speed at which the armature 
revolved depended upon the engagement of the clutch; at low speeds 
both shafts would turn at the same rate. As the driving-shaft speed 
increased, the governor decreased the pressure on the clutch spring, 
and the clutch faces slipped on one another, so that the driven shaft 
turned proportionately slower than the driving shaft. The earliest 
types of governors, employed about 1903 to 1905, were not successful, 
but about 1908 a type was developed that worked effectively on 
thousands of cars. It has since been superseded by electrical methods 
of regulation, and practically all of those now in use are electrically 
operated. 

Q. How many electrical methods of regulating the amount of 
current generated are in general use? 

A, So far as their principle goes, practically all are the same. 


ELECTRICAL EQUIPMENT 


699 


They depend upon weakening the excitation of the fields of the gen¬ 
erator to cut down the output. It is in the methods of accomplishing 
this that they differ. In the latter respect they may be divided into 
two general classes: those that are inherent in the design of the 
machine, i.e., the regulating device is actually a part of the machine 
itself; and those in which an external regulator is employed. Those 
most commonly employed are, in the first class, the bucking-coil 
winding and the third-brush method; in the second, an external 
regulator is usually combined with the battery cut-out and designed 
to keep either the voltage or the current at a uniform value, usually 
the voltage. 

Q. What is a bucking=coil winding, and why is it so called? 

A. We have seen that in a series-wound machine all of the 
current generated in the armature passes through the field windings 
and energizes the field magnets; in the shunt-wound machine the wires 
carry only a part of the current which is proportional to the resistance 
that the shunt winding of the fields bears to the resistance of the out¬ 
side circuit. As this outside resistance (the load) increases, more current 
will be diverted through the path of lesser resistance, or the shunt- 
wound field, and the output of the machine will increase accordingly. 
In the compound-wound machine, the relation of the series to the 
shunt winding is such that it is called upon chiefly to help carry any 
extra load. In other words, as the demands upon the machine 
increase, the series winding adds its energizing effect to that 
of the shunt coil. A generator with a bucking-coil winding is a com¬ 
pound-wound machine, but the series winding is in the opposite 
direction from that of the shunt winding. Consequently, instead of 
adding to the field excitation caused by the latter, it opposes or bucks it, 
and the more current there is produced in the shunt field by the rise 
in speed, the more the series winding, or bucking coil, tends to neutral¬ 
ize this excess, thus keeping the amount of magnetic effect produced 
in the field poles practically uniform, regardless of the speed. 

Q. What is the third=brush method of regulation? 

A. In a conventional shunt-wound generator, the field windings 
are directly in shunt with the armature through the brushes; hence, a 
certain proportion of all the current induced in the armature windings 
will find its way through the field magnet windings, in proportion 
to their relative resistance to the outside circuit at the time. W here a 


700 


ELECTRICAL EQUIPMENT 


third brush is employed, the main brushes are not in shunt with the 
fields, and they are not depended upon to supply the exciting current 
for the latter. The third brush instead is used for this purpose. As is 
well known, the output of a generator depends very largely upon the 
position of its brushes. In the immediate vicinity of the proper loca¬ 
tion for a brush, there is a short zone of maximum intensity. As we get 
away from this toward the next brush, it decreases until at a point 
midway between the two there is a neutral zone. The third brush is 
accordingly placed between the two main brushes, and its distance 
from the nearest main brush determines the amount of current that it 
diverts from the armature to the field windings. See illustration 

I 

of Delco generator in section on Methods of Regulation. This 
method has the advantage of supplying a strong shunt field at low 
speeds. As the speed increases, the voltage applied to the shunt field 
decreases, even though that between the two main brushes may have 
increased. 


Regulators 

Q. What is a regulator, and what is its purpose? 

A. It is an instrument somewhat similar to a battery cut-out, 
and its purpose is to regulate the output of the generator in order that 
the latter may not exceed safe limits at high speeds. The regulator 
is usually combined with the cut-out. 

Q. How does the constant=voItage type of regulator operate? 

A. The instrument consists of a magnet winding and a pivoted 
armature, normally held open by a spring and a resistance unit. 
The winding of the magnet has sufficient resistance to prevent the 
core becoming energized to a degree where it will attract the armature, 
unless the voltage exceeds the safe limit determined for the circuit. 
The voltage increases with the speed of the generator, so that when the 
latter is driven too fast the attraction of the magnet core for the arma¬ 
ture becomes sufficient to overcome the pull of the spring which 
normally holds the contacts apart. (See description of Bijur voltage 
regulator.) When the contacts come together, the field circuit of the 
generator is shunted through the resistance unit; this cuts down the 
amount of current energizing the fields, the voltage falls off, and the 
contacts again separate. Unless the speed of the generator is 
decreased, this action is rapidly repeated, so that the regulator arma- 


ELECTRICAL EQUIPMENT 


701 


tiire vibrates at a high speed as long as the voltage is sufficiently high 
to energize the magnet. 

Q. What is the principle on which this type of regulator 
operates? 

A. The principle that in a circuit having considerable self- 
induction the amount of current which may be sent through the 
circuit will decrease if the current be pulsating instead of steady. 
Every time the contacts of the regulator open, a pulsation, or surge, 
of current is sent through the field windings of the generator; when 
they close because of the higher voltage, the current is shunted 
through the resistance unit, thus cutting it down. The decrease in 
the amount of current is in proportion to the number of pulsations per 
minute, i.e., the rapidity with which the vibrating contact operates. 
The circuit having considerable self-induction is that of the- field 
winding of the generator, owing to its heavy iron core. (See Induc¬ 
tion.) 

Q. What is the constant=current type of regulator, and how does 
it differ from the constant=voltage, or potential, type? 

A. It consists of an electromagnet and a spring-controlled 
pivoted armature, so that it is of practically the same construction as 
the constant-potential type, but it is connected in circuit with the 
armature of the generator and it is wound to operate under the 
influence of the current rather than the voltage. Consequently, 
the pivoted armature is attracted, opening the circuit when the cur¬ 
rent exceeds a certain predetermined value, usually 10 amperes. In 
operation, the armature vibrates the same as in the voltage regulator, 
but the condition of the charge of the battery has no effect on it, so 
that when set to limit the current to 10 amperes, it will always charge 
the battery at approximately that rate regardless of the condition 
of the battery. The only practical difference is that it is wound to 
actuate under the influence of changes in the current flow and is 
connected in the armature circuit, whereas the constant-potential 
regulator is influenced by variations in the voltage and is connected in 
the field circuit of the generator. The latter has the advantage of 
charging the battery at a higher rate when the charge is most needed. 

Q. What other forms of regulators are employed on lighting 
generators? 

A. The foregoing comprise practically all of the principles 


702 


ELECTRICAL EQUIPMENT 


employed, but the regulators differ more or less in design and opera¬ 
tion. For example, in the Bosch-Rushmore generator, a bucking 
coil is employed in connection with what is termed a ballast 
resistor, or resistance unit. This is of iron wire, and it is based on the 
fact that resistance increases very rapidly with the temperature. 
The size of the wire is such that it allows 10 amperes to flow without 
undue heating, so that its resistance is practically unchanged; above 
this point it heats rapidly and increases in resistance so greatly that all 
excess current is shunted through the bucking coil. In the Splitdorf 
generator, the regulator is built in, projections of the pole pieces of the 
field being utilized in connection with special windings, instead of an 
independent electromagnet as in the Ward-Leonard and the Bijur. 
In the U.S.L. generator of the inherently regulated type, regulation is 
accomplished by the combination of a Gramme ring armature, a 
special arrangement of connections and of the field windings, and the 
use of only a part of the fields and armature for generating current. 
The regulation obtained is based on armature reaction and is similar 
in effect to the third-brush method. The U.S.L. external type of 
regulator cuts into the generator field circuit a variable resistance 
consisting of an adjustable carbon pile. In the Adlake regulator, 
which is of the constant-potential type, a solenoid operates a switch 
over the contacts of a variable resistance. The plunger of the sole¬ 
noid is counterbalanced by a weight, which must be raised to operate 
the switch. It is adjustable by increasing the weight of this counter¬ 
balance. 

Q. What attention does the regulation of the generator require? 

A. This will depend upon the method employed in each case. 
Where an external regulator is employed, whether of the constant- 
potential or the constant-current type, the attention required is 
practically the same as in the case of the battery cut-out. See that 
the points are not sticking, and when badly burned or pitted, smooth 
and true up, taking off as little of the contact point as possible to effect 
this. When the points have become so badly pitted that this cannot 
be done, new parts will be necessary. 

With the third-brush method, the attention required by this 
brush is the same as that which must be given the other brushes, i.e., 
sanding-in at intervals and replacement when worn too short to 
permit the spring to hold the brush firmly against the commutator. 


ELECTRICAL EQUIPMENT 


703 


Where the generator fails to produce sufficient current to keep the 
battery charged, all other parts of the system being in good condition 
and the car driven long enough in daylight to charge the battery under 
normal conditions, the position of the third brush may be shifted to 
increase the output. Care must be taken not to let it come in contact 
with the main brush. (See Delco instructions.) In the case of a 
bucking-coil winding, no attention is necessary, as this is an integral 
part of the machine itself. As the Splitdorf regulator has moving 
contact points, the attention necessary is the same as that required 
for an external regulator of this type. Special regulators, such as the 
U.S.L. external type, require attention covered by the maker’s instruc¬ 
tions. (See U.S.L. system.) 

Q. When the generator fails to keep the battery charged prop= 
erly, a normal amount of daylight driving being given the car, is the 
fault most likely to be found in the regulator? 

A. No. It is much more likely to be caused by a dirty commu¬ 
tator, worn brushes, loose connections, or some similar cause which 
inserts extra resistance in the charging circuit. The movement of 
the regulator armature is very slight, and the current handled by the 
contact points is small, so that it will seldom be the cause of the 
trouble. Other causes, such as those above enumerated, should 
always be sought first. (See instructions under Generator.) 

Windings 

Q. Are faults in the generator windings frequent? 

A. They constitute one of the least frequent sources of trouble 
with the machine. 

Q. What is likely to cause them? 

A. Dousing the machine with water is likely to be one of the 
most frequent causes of short-circuits or grounds in the generator 
windings. All electrical machinery is intended to be kept dry. 
Except where provided with a field fuse, running the generator when 
disconnected from the battery or with the battery removed from 
the car is another cause. Excessive speed, in some instances, may 
generate sufficient centrifugal force to lift the armature coils out 
of their slots so that the insulation becomes abraded by rubbing 
against the pole pieces, but this is very unusual. In rare instances, 
a hard kink left in the wire when winding may crystallize the metal 


704 


ELECTRICAL EQUIPMENT 


and make it break at that point, due to the vibration. Unless cleaned 
out at intervals, fine carbon dust from the wear of the brushes may 
accumulate in the interstices of the windings, and, when aggravated 
by moisture, this is apt to cause short-circuits. 

Q. What are the usual indications of such faults? 

A. With a short-circuited generator coil (armature), all other 
parts of the apparatus and circuits being in good condition, the 
charging rate will be lower than normal. The ammeter needle will 
vibrate violently when the engine is running at low speeds, and two 
or more adjacent commutator bars will burn and blacken. With 
an open armature coil (broken wire), the indications will be prac¬ 
tically the same, and there will be severe sparking at the brushes, 
causing serious burning of the commutator bar corresponding to 
the open coil. A grounded armature coil will give the same general 
indications, and if the machine is a single-unit type, the cranking 
ability of the starting motor will be seriously impaired. The 
ammeter, however, will not vibrate as in the former cases. There 
will be practically no charge from the generator, and the battery 
will be discharged very rapidly by the starting motor. 

In a single-unit machine, when the windings of the generator 
and the starting motor become interconnected, the indications 
will be practically the same as those of a grounded armature coil. 
If the motor windings of a single-unit machine become grounded, 
there will be an excessive discharge from the battery, while the 
motor will develop but little power. 

Q. How may such faults be located? 

A. With the aid of the testing-lamp outfit. Remove the 

t 

brushes (when replacing them later, be sure to put each brush 
back in the holder from which it was taken), or the brushes may 
be insulated from the commutator by placing paper under them. 
For a grounded coil, place one test point on the commutator and 
the other on the frame; if grounded, the lamp will light. For inter¬ 
connected motor and generator windings in a single-unit machine 
having two commutators, insulate the brushes as mentioned and 
place the test points one on each commutator. The light will burn 
if the two windings are connected. For a grounded-motor winding, 
test from the motor commutator to the frame; the light should 
not burn if the insulation is all right. For a break or open circuit 


ELECTRICAL EQUIPMENT 


705 


in the field winding, touch the terminals of the latter with the test 
points, the commutator being insulated or the armature removed. 
The lamp should light, h'or a blown field fuse on machines so 
equipped, place the points on the clips; if the fuse is intact, the 
lamp will light. 

Q. Are these tests conclusive? 

A. No. They will indicate any of the faults mentioned, 
but they will not reveal an internal short-circuit in the windings, 
which cuts some of the armature or field turns out of action but 
does not break the circuit as a whole. Such a short-circuit reduces 
the output of the generator and can be determined definitely only 
by measuring the resistance of the windings. This requires special and 
expensive testing instruments, such as the Wheatstone bridge, so that 
where all other tests fail to reveal the cause of a falling off in the out¬ 
put of the generator, it should be sent to the maker for inspection. 

Commutator and Brushes 

Q. What does a blackened and dirty commutator indicate? 

A. Sparking at the brushes or an accumulation of carbon 
dust due to putting lubricant on the commutator. 

Q. What is the cause of sparking at the brushes? 

A. Poor brush contact, due to worn brushes; brush-holder 
springs too loose, so that brushes are not held firmly against the 
commutator; excessive vibration, which may be due to a bent shaft, 
an unbalanced gear pinion, or improper mounting; using too much 
oil, or using grease in the ball bearings, which gets on the commutator 
and, acting as a solvent for the binder of the carbon, forms a pasty 
mass wLich prevents proper brush contact; worn or roughened 
commutator on which the mica needs undercutting; overload due 
to failure of regulator or to grounded coils in armature. 

Q. What is the remedy for sparking? 

A. Glean the commutator with fine sandpaper and sand-in 
the brushes to a true bearing on the commutator as directed in the 
Delco instructions. See that the brush springs have sufficient 
tension to keep the brushes firmly pressed against the commutator 
when the machine is running. If the mica protrudes above the 
commutator bars, it must be undercut as directed, and the commu¬ 
tator smoothed down again after the operation to remove any burrs. 


706 


ELECTRICAL EQUIPMENT 


Q. Why do some commutators need undercutting and others 

not? 

A. Undercutting is required only on machines equipped with 
brushes that are softer than the mica. Copper-carbon brushes, 
as employed on starting motors to reduce the brush resistance, are 
hard enough to keep the mica worn down with the copper of the 
commutator itself. 

Q. If, after smoothing off and undercutting the mica, the 
commutator still has an uneven and irregular surface, what is the 
remedy? 

A. The armature should be removed from the machine, and 
the commutator trued up in the lathe, taking as light a cut as possible 
consistent with obtaining a true round and smooth surface. 

Q. How can excessive commutator wear be prevented? 

A. Inspect at regular intervals and on the first sign of sparking 
smooth up the surface and sand-in the brushes. Keep the com¬ 
mutator clean and do not permit carbon dust or oil to accumulate 
in the commutator and brush housing. Never replace brushes or 
brush springs with any but those supplied by the manufacturer 
for that particular model. The machine will work with any old 
brush and any old spring that fits, but they will prove detrimental 
to its operation in a comparatively short time, and its ivorking under 
such conditions will never be satisfactory. 

Q. Is discoloration of the commutator ever caused by anything 
else than sparking? 

A. Not actual discoloration which requires cleaning, but the 
normal operation of the machine produces a purplish blue tinge on 
the bars, which is sometimes mistaken for discoloration by the 
inexperienced. This color, in connection with a high polish of the 
metal, indicates that the commutator is in the best of condition. 
Once the commutator takes on this high polish, it will operate for 
long periods without other attention than the removal of dirt by 
wiping with a clean rag. Sanding to remove this purple tinge is a 
mistake, as it only destroys the polish without having any beneficial 
effect. 

Q. Is it necessary to lubricate the surface of the commutator? 

A. No. The brushes employed are usually of what are termed 
a self-lubricating type and require no attention in this respect. 


ELECTRICAL EQUIPMENT 


707 


Q. Will any harm result from putting light grease, vaseline, or 
lubricating oil on the surface of the commutator? 

A. As all lubricants are insulators to a greater or less extent, 
the efficiency of the machine will be reduced and, as the voltage is 
very low, but a slight falling off is necessary to represent a very sub¬ 
stantial percentage of the maximum. The use of lubricant of any 
nature on the commutator also has another harmful effect in that it 
collects the carbon dust resulting from the wear of the brushes, caus¬ 
ing it to lodge against them as well as between the commutator bars. 

Q. Why should particular care be taken to remove all carbon 
dust from the commutator housing of both the generator and the 
motor (two=unit system) or the single unit where both functions are 
combined in one machine? 

A. Carbon dust is an excellent conductor of electric current 
and, when spread over the surface of an insulator, it causes the latter 
to become conducting as well. Consequently, it is likely to short- 
circuit the commutator bars by lodging between them. It will cause 
leakage across fiber or other insulating bushing of brush holders when 
a sufficient deposit accumulates on them. It will penetrate the arma¬ 
ture and field windings of the machine and may cause trouble by 
grounding or short-circuiting them. Especial care should be taken 
to remove all traces of carbon dust after sanding-in the brushes. 

Q. How often should the commutator be inspected? 

A. The commutator is the most vulnerable part of any direct- 
current machine, whether it be a generator or motor, and it should 
accordingly be inspected at more frequent intervals than any other 
single part of the entire system. The efficiency of both the generator 
and the motor depend upon it to a very great extent. Most of the 
failures of starting and lighting systems that are not due to poor 
condition of the battery may be traced directly to the commutator. 

Q. What is the function of the brushes? 

A. To conduct the voltage and current induced in the armature 
by its revolution through the lines of force created by the magnetic 
field, to the outer circuit, in the case of an electric generator; and to 
conduct the operating current to the armature windings from the 
battery, in the case of the starting motor. 

Q. Why must the brushes bear evenly over their entire surface 
on the commutator? 


708 


ELECTRICAL EQUIPMENT 


A. Because their current-carrying capacity depends upon their 
size, and the latter is based upon the entire surface of the end of the 
brush making efficient contact. If the brush does not make uniform 
contact, those parts of it that do not touch the commutator will cause 
arcing or heavy sparking at the gap thus created, resulting in 
damage to both the commutator and the brush. 

Q. Why are springs of different strengths used on generators 
and motors of different makes to hold the brushes against the commu= 
tator, though the machines are of practically the same capacity, 
operate at the same voltage, and are in other respects very much alike? 

A. The carbon compounds of which the brushes are manufac¬ 
tured differ greatly in their conductivity and resistance offered to the 
passage of the current, and these differences call for greater or less 
spring pressure to hold the brush against the commutator surface in 
order to make efficient contact over the entire surface of the brush. 
Every maker has his own standard in this particular respect. 

Q. Why is it not advisable to use brushes other than those 
supplied by the manufacturer as replacements on a machine? 

A. For the reasons just given above. The manufacturer has 
adopted certain standards for the operation of his machines, and the 
brushes supplied have been made particularly to comply with those 
standards. No other brushes will do so well, and some will result in 
injury to the machine. 

Q. When inspection shows that the brushes have worn down 
unevenly, what should be done? 

A. They should be sanded-in with a strip of fine sandpaper, 
such as No. 00, preferably already worn if the brushes are very soft. 
(See instructions for doing this properly in connection with machines 
of different makes.) No more should be removed than is absolutely 
necessary to bring the end of the brush to a firm contact all over its 
bearing surface on the commutator; and the end of the brush, after 
the completion of the operation, should not show any deep scratches 
or pit marks. Lmless the surface is smooth and true, injurious spark¬ 
ing will result, and the efficiency of the machine will be decreased. 

Q. If, with a smooth and true surface, the brush still fails to 
make good contact, what is the trouble? 

A. The brush has probably worn down until it is too short for 
the spring to exert sufficient force against it to hold it against the 


ELECTRICAL EQUIPMENT 


709 


commutator properly, or the spring itself may be at fault. Wear of 
the brush beyond the point where it is any longer of service will most 
often be the cause. 

Q. Where the brushes are true and are making good contact 
against the commutator, but the machine is inoperative, all other 
parts of the system being in good condition, what is likely to be the 
trouble? 

A. One of the pigtails, or short flexible connections, of the 
brushes may have shaken out from under its spring clip. This breaks 
the circuit, just as a parted wire or a ruptured connection at a terminal 
in any other part of the system would. 

Q. How often is it necessary to replace the brushes? 

A. This differs so much with different makes of machines that it 
cannot be answered definitely, even as an average. On two-unit 
systems, the generator brushes will naturally require replacements 
much sooner than those of the starting motor, as the starting motor is 
only in operation for very short periods, while the generator is working 
constantly. On single-unit types, this naturally does not apply, as, 
whether the armature has one or two sets, they are always in use. 
Ordinarily, brushes should not require replacement under a year, and 
frequent instances are known of their having lasted for two years or 
more. It depends upon the care given the commutator and brushes 
quite as much as upon the mileage covered, as, if allowed to run dirty 
for any length of time, the brushes will wear away much faster than if 
kept in good condition. The best rule for the replacement of the 
brushes on all makes of machines is to renew them as soon as they 
have worn to a point where the springs no longer hold them firm 
against the commutator. When they have reached this condition, the 
vibration and jolting of the car is likely to shake them out of contact, 
which results in sparking. 

Q. What is the “third brush’', and what is its function? 

A. This is an extra brush used on a generator. Its purpose is to 
control the amount of current supplied by the armature to the shunt- 
field winding as the speed increases. In other words, it regulates the 
output of the machine and prevents it from being burned out when 
the speed of the engine becomes very high. 

Q. Does it differ from the other brushes in construction or in 

the care required? 


710 


ELECTRICAL EQUIPMENT 


A. It is a carbon brush of the same nature as the others used on 
the same machine, and the care required to keep it in good condition 
does not differ. However, it is mounted in an independently adjust¬ 
able holder so that it may be moved backward or forward with relation 
to the main brushes in order to increase or decrease the output of 
the generator. (See instructions [Delco] on this point.) 

Q. Is it ever necessary to alter the location of the brushes 
of a machine? 

A. Except on generators fitted with the third-brush method of 
regulation, on which it may be necessary to shift the main brushes 
slightly to avoid having the third brush come in contact with one of 
them when moved to change the output, it should never be necessary 
to shift the location of the brushes. Brush location has an important 
bearing on the operation of the machine, and, in designing it, the maker 
has fixed the location of the brushes to conform to its other charac¬ 
teristics. Many machines have no provision for adjusting the 
brushes in this respect, while some manufacturers caution the user 
particularly against altering their location. 

Q. How much spring pressure is usually employed to hold the 
brushes of the generator and starting motor against the commutator? 

A. This varies with different makes of machines and should be 
ascertained from the maker’s instructions in every case in order to 
check up properly. In the various models of the Gray & Davis 
starting motors, this spring pressure ranges from 2j to 3| pounds, 
which is the minimum necessary. In other words, the brush must be 
held against the commutator with this amount of pressure in order to 
operate efficiently. While there will be a loss if the pressure drops 
below the minimum, there is no advantage in greatly exceeding it, as 
excess pressure simply causes greater friction loss without any com¬ 
pensating gain in power. Generator-brush pressures are much less 
than those employed on starting motors, owing to the smaller amount 
of current handled. 

Q. How can the proper spring pressure of the brushes be 
checked? 

A. With the aid of an ordinary spring scale of the direct-pull 
type, in which the pull on the hook draws the pointer down over the 
scale. A scale reading to five pounds is adequate for the purpose; 
one intended for heavy weights is not likely to be so accurate. Attach 


ELECTRICAL EQUIPMENT 


711 


the hook of the scale to the brush and pull until the brush is just clear 
of the commutator. The scale will then register the pull in pounds. 
Where there is nothing on the brush to which to attach the hook, such 
as a screw, place a thin piece of wood on the brush face before passing 
the hook of the scale around it, to prevent injuring the contact face 
of the brush. In this case, the spring pressure as shown on the scale 
will exceed the necessary minimum, as the spring must be compressed 
further than it would be when in operation, in order to operate the 
scale. This should be allowed for when taking the reading. 

Q. When is it advisable to check the spring pressure of the 
brushes? 

A. When there is undue sparking at the commutator, while the 
commutator and brushes are all in proper condition, i. e., clean, and 
bearing uniformly over their entire surface so that the sparking is not 
due to any fault in either of these essentials. 

Q. When the brushes and commutator are in good condition 
and the spring=scale test shows that the brushes are being held 
against the commutator with the necessary amount of pressure, what 
is likely to be the cause of the sparking? 

A. There may be a short-circuited or open coil in the armature. 

STARTING MOTOR 

Q. In what way does the starting motor of a two=unit system 
differ from the generator? 

A. It is a simple series-wound machine having but one winding 
of coarse wire on the fields, and all the current from the battery 
passes through its armature coils and field windings. 

Q. Is it subject to electrical faults other than those already 
referred to in connection with the generator? 

A. No. The care and the nature of the tests required to 
locate faults are the same. The commutator should be kept clean, 
brushes bearing firmly on commutator, and all connections kept 
tight. The same instructions for sanding-in brushes and keeping 
the commutator in good condition apply as in the case of the 
generator. 

Q. When the starting motor fails to operate, what is likely 
to be the cause? 

In the majority of instances, a low state of charge or a 


712 


ELECTRICAL EQUIPMENT 


wholly discharged battery will be responsible. If the battery is 
all right, a loose connection at the battery, switch, or motor, or a 
short-circuit in some part of this wiring may be the cause. Should 
the battery be properly charged, all wiring and connections in good 
condition, switch contacts clean, etc., the starting gears may be 
binding, owing to dirt or lack of alignment between the motor shaft 
and the flywheel of the engine. In this case, the motor will attempt 
to start when the current is first turned on, but will be held fast. 
Loosen the holding bolts and line up the motor, cleaning the gear 
teeth if necessary. 

Q What is likely to be the cause of the starting motor running 
slowly and with very little power? 

A. Exhausted battery, poor switch contacts, loose connec¬ 
tions, partial ground or short-circuit in wiring causing leakage, 
improperly meshing gears, dirty commutator, brushes making poor 
contact owing to weak springs or worn brushes, or a ground in the 
motor itself. The remedies for all these faults have been given already. 

Q. When the battery and all connections and wiring are in 
good condition, but the motor fails to crank the engine, what is likely 
to be the cause? 

A. The engine may be too stiff. If it has been overhauled 
just previously, the main bearings may have been set up too tight. 
Test with the starting crank to see if it can be turned over easily 
by hand. If unusual effort is required, easing off the bearings should 
remedy the trouble. Should the engine not turn over as soon as 
the switch is closed, release immediately, as otherwise the battery will 
be damaged. 

Q. When the engine does not start within a few seconds, why 
is it better to use the starting motor intermittently than to run it con= 
tinuously until the engine does fire? 

A. The intermittent use of the starting motor, say ten seconds 
at a time, with a pause of half a minute or a minute between attempts 
is easier on the battery. If allowed to rest for a short period, the 
storage battery recuperates very rapidly. Consequently, the opera¬ 
tion of the starting motor for two minutes, divided into twelve periods 
of ten seconds each, will not run the battery down to anything like the 
extent that its continuous operation for the same length of time would. 
Moreover, this intermittent method of operation increases the chances 


ELECTRICAL EQUIPMENT 


713 


of starting under adverse conditions, as, in very cold weather, every 
time the battery is allowed to rest, it will be able to spin the engine at 
its normal starting speed, whereas if the starting motor is operated 
continuously, the battery will become so weak that the engine will be 
turned over very slowly toward the end of the period in question. 

Q. Why is it that a starting motor capable of turning an engine 
over at a speed anywhere from 75 to 150 r.p.m. will sometimes fail 
to start the engine, whereas hand cranking subsequently resorted 
to will succeed? 

A. It must be borne in mind that the operation of starting an 
engine in cold weather involves several factors. (1) The pistons, 
crankpins and crankshaft (bearings) must be broken away, i.e., 
forcibly released from the hold that the gummed lubricating oil has on 
them, before they can be moved. The great difference between the 
power required to do this in summer and in winter is shown by the 
greatly increased amount of current used by the starting motor. 
(2) Gasoline and air must be drawn into the cylinders, to effect which 
in sufficient quantity to start the engine requires quite a number of 
revolutions. (3) The gasoline must be vaporized so that it will mix 
with the air, which involves more turning of the engine to create the 
necessary heat by compression in the combustion chambers and the 
friction of the moving parts. In the application of energy in any 
form, two factors are always involved, i.e., the unit, or quantity of 
power applied, and the length of time during which it is applied. The 
starting motor cranks the engine at a comparatively high speed for a 
brief period. In hand cranking, a smaller unit of power is employed, 
and the speed of cranking is accordingly less, but its application is 
continued for a much longer time. The failure of the starting motor is 
not due to its inferiority to hand cranking, but simply to the fact that 
the battery has become exhausted. Success in hand cranking where 
the starting motor has failed is usually due to the fact that the starting 
motor has done all the preliminary work, failing in the end simply 
because the storage battery did not have sufficient energy to finish 
the task. No electrical starting system can ever be any stronger than 

its storage battery, or source of energy. 

Q. Wh> is it not necessary to protect the starting motor or its 
circuit by fuses or other protective devices as in the case of the 
generator? 


714 


ELECTRICAL EQUIPMENT 


A. A simple series-wound machine (practically all electric start¬ 
ing motors are of this type) is capable of standing exceedingly heavy 
overloads for short periods, it being nothing unusual for these small 
motors to have a factor of safety of five, or even seven, for a limited 
time, that is, they will take five to seven times the normal amount 
of current for a brief period without injury. As a matter of fact, the 
starting motor can utilize all the current the battery is capable of 
supplying, provided the motor is free to move. If the engine is stuck 
fast or some part of the starting system has gone wrong so that the 
electric motor cannot turn over, then there is danger that the motor 
may be damaged unless the switch is opened at once. This, together 
with the fact that the maximum load which may be placed on the 
motor at different times is such a variable quantity, would make it a 
difficult matter to provide a fuse that would not blow unnecessarily. 
The only object of the fuse would be to protect the motor windings, 
and, as the latter can stand all the current the battery can supply, the 
only source of danger is the possibility of the motor being held fast 
so that its armature cannot revolve. 

WIRING SYSTEMS 
Different Plans 

Q. What is the difference between the single=wire and the 
two=wire systems? 

A. In the single-wire there is but one connection to the operat¬ 
ing circuit by means of a wire or cable, the circuit being completed 
in every instance by grounding the other side of the circuit. For 
this reason the single-wire is also referred to as a grounded system. 
In the two-wire system, copper wires or cables are employed to com¬ 
plete the circuits between the generator and battery and between 
the battery and the starting motor, as well as to the lamps. 

Q. What forms the return circuit of a single=wire system? 

A. The steel frame of the chassis. 

Q. How are the various circuits grounded? 

A. In the case of the battery, a special ground connection is 
usually made by drilling the frame and fastening a clamp to it. 
The ground cable from the battery is attached to this clamp. The 
generator and starting motor are grounded internally, i.e., the end 
of a winding or of a brush lead that would be taken out to form the 


ELECTRICAL EQUIPMENT 


715 


return side of a two-wire system is connected to the frame of the 
machine, and the latter completes the connection to the chassis 
through its holding bolts or other means of attachment. One side 
of all lamp sockets is usually grounded, so that the bulb itself com¬ 
pletes the connection when fastened in place. Sometimes there 
is a special ground connection from the battery for the return side 
of the ignition or lighting circuits, and this ground wire is fused. 

Q. What are the advantages and disadvantages of the single= 
wire system? 

A. It greatly simplifies the wiring, as but one wire connection 
is necessary to the apparatus for each circuit, but this advantage 
renders it more susceptible to derangement through unintentional 
grounds or short-circuits, since the touching of any metal part of 
the chassis by a bare wire will cause a short-circuit. This depends 
to a very great extent, however, on the thoroughness with which 
the wiring is protected, and, with the armored cables or loom and 
the junction boxes used on modern installations, it is reduced 
to a point where both systems are practically on a par in this 
respect. 

Q. What are the advantages and disadvantages of the two= 
wire system? 

A. Each circuit is complete in itself thus rendering it easier 
to locate faults, while no one connection coming in contact with 
a metal part of the chassis will cause a ground. The wiring itself, 
however, is much more complicated, and, with the small space 
available on the bulb connections, it is more difficult to insulate 
them properly. 

Q. Which system of wiring is favored? 

A. The single-wire system will be found on the majority of 
cars, and the number of makers adopting it is steadily increasing. 

Faults in Circuit 

Q. What is the difference between a ground and a short= 
circuit? 

A. So far as the effect produced is concerned, they are the 
same; the difference in the terms referring solely to the method of 
producing it. For example, if the cable of the starting motor circuit 
becomes abraded and the bare part touches the chassis or some 





716 


ELECTRICAL EQUIPMENT 


connecting part of metal, this is a ground. But it is also a short- 
circuit in that the circuit to the battery is completed through a 
shorter path than that intended. On the other hand, if, in a two- 
wire system, the two cables of the same circuit become chafed close 
together and their bared parts touch, this is a short-circuit, but 
it is not a ground. For all practical purposes, however, the two 
terms are really interchangeable when applied to faults in the circuit. 
(See Gray & Davis instructions.) 

Q. How may grounds be located in a single=wire system? 

A. In any of the fused circuits, the fuse will immediately 
blow out. Remove the fuse cartridge and shake it; if it rattles, 
the fuse wire has melted and the fuse is blown. If it does not 
rattle, short-circuit the fuse clips with the pliers or a piece of metal; 
a spark will indicate the completion of the circuit and will also 
indicate that the fuse has blown. If, on bridging the fuse clips, 
the lamp lights, or other apparatus on the circuit operates, the 
short-circuit was only temporary. This does not mean, however, 
that the fault has been remedied; the vibration of the car may 
have shaken whatever caused it out of contact and further vibra¬ 
tion sooner or later will renew the contact with the same result. 
Inspect the wiring of that particular circuit and note whether the 
insulation is intact throughout its length. See that no frayed ends 
are making contact at any of the connections and that the latter 
are all tight and clean. In case the lamp does not light on bridging 
the fuse clips, see if the bulb has blown out; if not, use the test 
lamp by applying one point to the terminal and the other to various 
points along the wiring. 

Q. Does the blowing of a fuse always indicate a fault in the 
wiring? 

A. No. A bulb, in blowing out, frequently will cause a tem¬ 
porary short-circuit that will blow the fuse. To determine this, 
apply the points of the test-lamp outfit to the bulb contacts; if the 
test lamp lights, the bulb is short-circuited, and a new fuse and bulb 
may be inserted without further inspection of the circuit. In case 
the test lamp does not light on this test, it does not necessarily 
indicate a fault in the wiring of that circuit, though inspection is 
recommended before putting in new fuse and bulb. The blowing 
out of the bulb may cause a short-circuit, which is ruptured by the 


ELECTRICAL EQUIPMENT 


717 


current burning away the light metal parts that were in contact, 
such as a small piece of the filament. 

Q. Can a short=circuit or ground occur without blowing a fuse? 

A. Yes. No fuses are employed on starting-motor circuits 
owing to the very heavy current used and its great variation depend¬ 
ing upon the conditions, such as extreme cold gumming the lubri¬ 
cating oil, tight bearings, binding of the pinion and gear, sprung 
shaft, starting motor out of alignment, or the like. On other circuits, 
the amount of current leaking through the fault in the circuit may 
not be sufficient to blow the fuse, as the capacity of the latter is 
such that it will carry the maximum current which the apparatus in 
that circuit will carry without damage—usually 5 or 10 amperes 
on lighting circuits and 10 amperes on generator-field circuits. 

Q. How can such faults be noted? 

A. The ammeter, or indicator, will show a discharge reading 
when the engine is idle and all lamps are switched off. 

Q. What is the usual nature of such a fault? 

A. The battery cut-out may have failed to open the circuit 
completely; a frayed end of the stranded wire at one of its con¬ 
nections may be making light contact which will permit a small 
amount of current to pass; a particle of foreign matter of high 
resistance may be bridging a gap either at the cut-out or some 
other part of the circuit; or the ignition switch may have been 
left on the battery contact so that current is flowing through the 
ignition coil. 

Q. How may faults be located in a two=wire system? 

A. With the aid of the test lamp, placing the points along 
the two wires of the circuit at fault from one set of terminal con¬ 
nections to the other, examine all connections in the circuit in 
question; note wffiether any wires have frayed ends and, if so, wind 
them tight together and dip in molten solder. See whether any 
moving part is in contact with one or both of the wdres and whethei 
the insulation of the latter has been worn off. In some two-wire 
systems there is a ground connection to the battery for the ignition 
system, in w^hich case tests for grounds in the circuit in question 
must also be made. Examine the ignition switch for faults; also 
the switch of the circuit under test. This applies to single-wire as 
wxll as to tw^o-wdre systems, 


718 


ELECTRICAL EQUIPMENT 


Q. What is one of the most frequent causes of short=circuits 
in a two=wire system? 

A. The bulbs and their sockets, owing to the very small 
amount of space available for the insulation. Dirt or particles of 
metal may be bridging the small gaps between their insulated con¬ 
tacts. A blown-out bulb also may be responsible, as previously 
mentioned. 

Proper Conduction 

Q. Why are different sizes of wire employed in the various 
circuits? 

A. To permit the passage of the maximum current necessary 
in each circuit consistent with the minimum drop in voltage due 
to the resistance of the wire and its connections. The voltages 
employed are so low that any substantial drop due to this cause 
would seriously impair the efficiency of the system and particularly 
of the starting motor. For the latter the cables employed are not 
only large, but they are also made as short and direct as possible 
to save current as well as expense in the installation. 

Q. What is the smallest wire that should be employed in 
automobile wiring? 

A. No. 14 B. & S. gage, and this should be used only for the 
tail lamp, dash lamp, primary circuit of the ignition, or similar 
purpose. No. 10 or No. 12 is usually employed for the other lighting 
circuits. 

Q. When, in making alterations on a car, it becomes neces= 
sary to extend a circuit, what should be done? 

A. The ends of the wires should be scraped clean and bright 
for at least 2 inches, and a lineman’s joint made with the aid of 
the pliers to insure having it tight. A lineman’s joint is made by 
crossing the bared ends of the wires at their centers at right angles 
to each other, then wrapping or coiling each extending end tight 
around the opposite wire; the joint then should be soldered and 
well taped. A circuit should be extended only by using wire of the 
same size and character of insulation. None of the foregoing applies 
to the starting-motor circuit. It is inadvisable to lengthen this 
circuit if avoidable, but in the rare instances when it would be 
necessary, new cable of the same size or larger and with the same 
insulation should be cut to the proper length and the old cable 


ELECTRICAL EQUIPMENT 719 

discarded. All terminals should be solidly fastened to the new cable 
by soldering. 

Q. Why is it necessary to use such heavy cable for the connec= 
tion of the starting motor to the battery? 

A. It is essential that the exceedingly heavy starting current 
be transmitted with the minimum of loss. 

Q. What is considered the minimum permissible loss in the 
starting=system wiring? 

A. One maker specifies that the starting cable must be large 
enough to transmit a maximum current of 400 amperes with not over 
one-fourth volt total loss. 

Q. Why is it important to hold the voltage drop down to a maxi= 
mum so small as to be negligible in almost any other application? 

A. Owing to the heavy current necessary, as a drop of but J 
volt in potential with a current of 400 amperes represents a loss of 100 
watts, or close to y horsepower. Of course, the current seldom 
reaches such a high value as this except when a motor is exceptionally 
stiff, as in severe cold weather or just after its bearings have been set 
up very tight; moreover, this loss takes place at the instant of starting 
only, but it is just at this time that the highest efficiency and full 
battery power is needed to start without spinning the engine too much. 

Q. On some of the early systems whose efficiency was not of 
the best, how can the proper size of cable to use between the starting 
motor and battery be determined? 

x\. Test the starting motor with a high-reading ammeter (scale 
should read to at least 300 amperes) after having made certain by 
hydrometer and voltage tests that the storage battery is fully charged. 
(See instructions regarding this.) Carefully note ammeter reading 
exactly at instant of closing switch, to determine maximum current 
flow. Measure the length of cable between the battery and the 
starting motor, i.e., both sides of starting switch. Then maximum 
starting current times 10.7 times number of leet of cable used, divided 
by .25 will give the cross-section of the wire in circular mills. For 
example, assume that the starting motor required a maximum of 300 
amperes momentarily to break away the engine, and five feet of 
cable are employed for the connections. Then 

30nxl0-< _:^^ 128,400 circular mills 
‘>5 



720 


ELECTRICAL EQUIPMENT 


By referring to Table I, Part I, which gives the various size wires in 
circular mills and their equivalent in gage sizes, it will be noted that 
the closest approach to this is No. 00 cable, which is 133,079 circular 
mills, so that the largest size cable would have to be used. If the 
starting cable used on an old system which does not show particularly 
good efficiency is much smaller than this, it would probably be an 
advantage to replace it with larger cable, assuming, of course, that 
every other part of the system is in good condition and working 
properly. 

Q. Why should connections be inspected frequently? 

A. The vibration and jolting, to which they are subjected in 
service is so severe that no mechanical joint can be depended upon 
to remain tight indefinitely. 

Q. What harm does a loose or dirty connection occasion? 

A. A loose connection causes the formation of an arc between 
its contacts whenever vibration causes the parts to separate tem¬ 
porarily. This wastes current and burns the metal away, leaving 
oxidized surfaces which are partially insulating, thus increasing 
the resistance at the connection. Dirt getting between the surfaces 
of the connector has the same effect; the resistance is increased and 
there is a correspondingly increased drop in the voltage of the 
circuit, which cuts down its efficiency. 

Q. Why should all terminals be well taped when the battery, 
starting motor, generator, or other apparatus is temporarily dis= 
connected for purposes of inspection or test? 

A. To prevent accidental short-circuits which would be caused 
by these terminals coming in contact with any metal part of the 
chassis on a single-wire system. Such a short-circuit would ruin 
the battery and burn out any lamps that happened to be included 
in the circuit. This precaution applies with equal force to the two- 
wire systems, as in this case the terminals of the different wires 
might come together, or there might be a ground connection in 
the system. 

PROTECTIVE AND OPERATIVE DEVICES 

Q. What are the protective devices usually employed on 
electric systems? 

A. Fuses in the separate lamp circuits, in the ground con- 


ELECTRICAL EQUIPMENT 


721 


nection, and in the field circuit of the generator on some machines; 
battery cut-out for the charging circuit; circuit-breaker which 
takes the place of the fuses. 

Fuses 

Q. What is a fuse and what is its function? 

A. A fuse consists of a piece of wire of an alloy which melts 
at a low temperature and which will only carry a certain amount of 
current without melting, the latter depending upon the diameter 
of the wire, i.e., cross-section and the nature of the alloy. The fuse 
is usually in the form of a cartridge, the wire being encased in an 
insulating tube having brass ends, to which the ends of the wire are 
soldered. These brass ends are pressed into spring clips to put the 
fuse in circuit. In some cases open fuse blocks are employed, the 
wire itself simply being clamped under the screw connectors on the 
porcelain block. The function of the fuse is to protect the battery 
and the lamps when, by reason of a ground or short-circuit in the 
wiring, an excessive amount of current flows. 

Q. When a fuse blows out what should be done? 

A. Investigate the cause before replacing it with a new one. 
(See Wiring Systems.) 

Q. Is it permissible to bridge the fuse gap with a piece of 
copper wire when no replacements are at hand? 

A. Only in cases of emergency and after the short-circuit 
which has caused the fuse to blow has been remedied. The finest 
size of copper wire at hand, such as a single strand from a piece of 
lamp cord, should be used. If this burns out, there being no ground 
or short-circuit in the wiring, use two strands. Remove the wire 
as soon as a new fuse is obtainable. 

Q. Why are fuses not employed in the starting=motor circuit? 

A. In the starting circuit the current necessary is so heavy 
and varies so widely with the conditions that it would not be 
practicable to provide a protecting fuse. 

Q. What does the intermittent blowing of the fuse on the same 
circuit indicate? 

A. A short-circuit that is caused by the vibration, or jolting, of 
the car. The wire, lamp socket, or other part of the circuit that is at 
fault is shaken loose at times so that the circuit is operative, and a new 


722 


ELECTRICAL EQUIPMENT 


fuse may be inserted without instantly blowing, as it would do were 
the short-circuit constant. This is often the case as the car is stopped 
to inspect the wiring and insert the new fuse, and standing still lets the 
part drop out of contact; starting up shakes it into contact once 
more and blows the new fuse. Loose connections, wires with abraded 
insulation, and bulbs loosely inserted in their sockets are apt to cause 
trouble of this nature. 

Q. Does the blowing out of a fuse necessarily indicate a fault in 
the wiring or in some other part of the system? 

A. No, since a bulb in burning out will frequently cause the fuse 
to blow out. This is due to the fact that in breaking, the end of the 
parted filament of the bulb may fall across the other terminal where it 
comes through the glass, thus causing either a short-circuit or such a 
reduction in the ordinary resistance as to permit a much heavier rush 
of current than normal, with the result that the fuse goes. To test, 
leave burnt-out bulb in place temporarily; short-circuit fuse clips with 
screw driver or pliers, just touching them momentarily; if no spark 
results, replace bulb with a new one and test again; if a spark occurs, 
remove old bulb and test again with no lamp in place; then if no spark 
occurs in bridging the fuse terminals, the circuit is all right, and the 
fuse may be replaced. 

Q. When all the lighting fuses blow out at once, what does 
this indicate? 

A. A short-circuit across the lighting-switch terminals would 
cause this. In some switches with exposed rear terminals, it is 
possible to place a screwdriver or similar piece of metal in such a posi¬ 
tion that it bridges practically all the switch terminals. If the light¬ 
ing switches were all closed at the time, this would short-circuit them. 

Circuit=Breaker 

Q. What is a circuit=breaker, and what is its function? 

A. The circuit-breaker is an electromagnet with a pivoted 
armature and contacts, similar in principle to the battery cut-out. 
All the current used in the various circuits, except that of the start¬ 
ing motor, passes through it, and its contacts normally remain closed. 
The winding of the magnet coil is such that the normal current 
used by the lamps or ignition does not affect it, but the passage 
of an excessive amount of current will energize the magnet, attract 


ELECTRICAL EQUIPMENT 


723 


the armature, and break the circuit. The spring holding the arma¬ 
ture away from the magnet will again close the circuit, and the 
circuit-breaker will vibrate until the cause has been removed. This 
is usually a ground or short-circuit. The function of the circuit- 
breaker is to protect the battery and lamps in place of the usual fuses. 

Q. If the circuit=breaker operates when there are no faults 
in the wiring, what is likely to be the cause? 

A. Its spring may have become weakened so that the vibra¬ 
tion of the car causes it to operate on less current. The Delco 
circuit-breaker is designed to operate on 25 amperes or more, but, 
once started, a current of 3 to 5 amperes will keep it vibrating. 
If tests show that no faults in the wiring or connections exist, 
increase the spring tension with the ammeter in circuit until the 
reading of the latter indicates that the circuit-breaker is not operat¬ 
ing on the current of less value than that intended. See that the 
contacts are clean and true. 

Battery Cut=Out 

Q. What is a battery cut=out? 

A. It is an automatic double-acting switch which is closed 
by the voltage of the generator and opened by the current from 
the battery. 

Q. Of what does it consist? 

A. It is essentially a double-wound electromagnet with a 
pivoted armature and a pair of contacts. One winding, known as 
the voltage coil, is of fine wire and is permanently in circuit with the 
generator. The second winding of coarse wire is termed the current 
coil and is put in circuit by the contacts. 

Q. Why is a cut=out necessary? 

A. To protect the storage battery. When the generator 
speed falls below a certain point, it no longer produces sufficient 
voltage to charge the battery, and the latter then would discharge 
through the generator windings if not prevented. This discharge 
would always take place when the generator was idle, except for 
the cut-out. 

Q. How does it operate? 

A. When the generator voltage approaches the value nec¬ 
essary for charging, it energizes the magnet through the voltage 



724 


ELECTRICAL EQUIPMENT 


coil and closes the contacts, cutting in the current coil, which fur¬ 
ther excites the magnet and holds the contacts firmly together. 
The closing of these contacts puts the battery in circuit and it 
begins to charge. As soon as the generator speed falls below the 
point necessary for charging, the battery voltage overcomes that 
of the generator and sends a current in the reverse direction through 
the current coil, causing the contacts to separate and cutting the 
battery out of the charging circuit. 

Q. If the generator is run for any length of time at or near 
this critical speed, what is to prevent the cut=out from vibrating 
constantly instead of working positively one way or the other? 

A. The resistance of the windings is so proportioned that 
there is a difference of 1 to 2 volts between the cutting-in and the 
cutting-out points. 

Q. What is the result when the battery cut=out—which is 
variously termed a cut=out, a circuit=breaker, an automatic switch, 
and a reverse=current relay or an automatic relay — fails to operate? 

A. If it fails to cut in, i.e., the contacts do not come together, 
the battery does not charge and will quickly show a falling-off in 
capacity, such as inability to operate the starting motor properly or 
to light the lamps to full brilliance. If it fails to cut out, the battery 
charge will be wasted through the generator windings with the same 
indications of lack of capacity. 

Q. What is the most frequent cause of trouble? 

A. Automatic cut-outs have been perfected to a point where 
but little trouble occurs. Freezing or sticking together of the 
contacts due to excessive current will most often be found to be 
the cause of the device failing to cut out when the generator is 
stopped. The points should be cleaned and trued up as described 
in previous instructions. Loose or dirty connections making poor 
contact may insert sufficient extra resistance in the circuit to 
prevent the device from cutting in at the proper point. Excessive 
vibration, particularly when the cut-out is mounted on the dash, 
may prevent the contacts from staying together as they should 
when the engine is running at or above the proper speed. See that 
the cut-out is solidly mounted. Temporary loss of battery capacity 
may be due to slow driving over rough roads at about the speed 
at which the cut-out is designed to put the battery in circuit. 


ELECTRICAL EQUIPMENT 725 

Q. None of the above causes existing, what further tests may 
be made? 

A. The windings may be tested as already described for the 
generator windings, but trouble from this source is equally rare. 
If the contacts are clean and true and the connections are tight, 
look for a loose connection elsewhere, as at the generator or battery 
or the ground on the frame. A loose connection vibrates when the 
car is moving, constantly opening and closing the circuit and causing 
the cut-out to do likewise, so that the battery does not charge. A wire 
from which the insulation has been abraded will also vibrate, owing 
to the movement, causing an intermittent short-circuit. With all con¬ 
tacts and connections in good condition, failure to cut out indicates a 
ground or short-circuit between the battery and cut-out; failure to cut 
in indicates similar trouble between the generator and the cut-out. 

Q. Is a battery cut=out necessary on every electrical system? 

A. No. On single-unit systems of the type of the Dyneto, 
in which the generator becomes motorized as soon as its speed and 
consequently its voltage drops below a certain point, the battery 
is always in circuit. A plain knife-blade switch, which also controls 
the ignition, is closed to start and left closed as long as the car is 
running. But the engine must not be allowed to run at a speed 
below which it generates sufficient voltage to charge the battery, 
nor must the switch be left closed when the engine is not running; 
otherwise, the battery will discharge through the generator windings. 

Q. After having trued up points of a battery cut=out, what pre= 
cautions should be taken in adjusting them? 

A. To insure proper operation, they must be set to the distances 
given in the manufacturer’s instructions. This refers not only to the 
gap between the contact points themselves, but also to the distance 
that the armature must be set from its backstop when the points are 
open and to the air gap between the armature and the magnet. 
These distances are very small in every case, and it is important that 
they be adjusted accurately. They differ slightly on cut-outs of 
different makes and also on different models of the same make. For 
example, in the Gray & Davis cut-out, the distance between the con¬ 
tact points should be .015, the air gap between the armature and its 
backstop not less than .010, and the armature air gap, or distance 
between the armature and the magnet face, .030. These dimensions 


726 


ELECTRICAL EQUIPMENT 


refer to the flexible, or spring-arm type, while in the solid-arm type 
of the same make, they are .010 for the distance between the contact 
points and .015 for the armature air gap, it being necessary that the 
armature should be set parallel with the pole face of the magnet. 

Q. How can these small distances be accurately determined 
with the facilities ordinarily found in a repair shop? 

A. The manufacturers usually supply a small adjusting wrench, 
the different edges of which have been ground to varying thicknesses 
representing the proper distances for the various gaps. Lacking one 
of these, small pieces of strip brass or steel may be ground or filed 
down to the proper size and gauged with a micrometer, which should 
be part of the equipment of every garage. The strips should be 
stamped with the dimensions and name of gap for identification. 

Q. How often will the point of a battery cut=out need adjust= 
ment, or truing up? 

A. Service conditions vary so greatly that it is impossible to give' 
any definite average for this, particularly as the instruments them¬ 
selves also are a variable quantity, but, under ordinarily favorable 
conditions, they should not require attention more than once a year. 

Contact Points 

Q. Why is it necessary to make contact points of such an expen¬ 
sive metal as platinum, and why is the latter sometimes alloyed with 
irridium? 

A. There is no other metal which withstands the oxidizing 
effect of the electric arc and still maintains a clean and bright con¬ 
ducting surface as does platinum. Irridium is added to make the 
platinum harder, so that it will be more durable. On cheaply made 
instruments in which no platinum has been used in the contacts, 
trouble will be experienced constantly with the contacts. 

Q. Is there any substitute for platinum or any metal that 
approaches it in adaptability for contact points? 

A. There is no substitute for platinum, and the only metal that 
approaches it is silver. Where contact points only separate occa¬ 
sionally at intervals, as in the Remy thermoelectric switch, the use of 
silver contacts is permissible; but in a battery cut-out, or a regulator 
in which the vibration of the points is more or less constant, nothing 
will serve so reliably as platinum. 


ELECTRICAL EQUIPMENT 


727 


Q. What is the cause of the platinum contacts burning into such 
irregular ragged forms? 

A. W hen a current of electricity passes through a contact of this 
nature, the material of the positive electrode (i.e., contact point 
connected to the positive side of the circuit) is carried over by the 
current in the shape of metallic vapor, or infinitely fine particles, and 
deposited on the negative electrode. The positive consequently takes 
on the form of a sharp point, while the negative has a depression 
formed in it, usually referred to as a “peak and crater”, which the two 
points resemble in miniature after long use. This peak and crater 
effect is much more noticeable in an old-style carbon arc lamp after 
it has been burning only a few hours. 

Q. What can be done to prevent this? 

A. The passing of the metal from one electrode to the other 
cannot be prevented, as it is a function of any arc or spark. It can 
be minimized, however, by keeping the contacts in good condition so 
that the sparking is reduced to a minimum. 

Q. Can the formation of the pack and crater effect, which so 
greatly reduces the efficiency of the contacts, be avoided? 

A. The use of a reversing switch in the circuit, as in the case of 
the magneto or the battery-type interrupter which changes the direc¬ 
tion in which the current flows through the points every time it is 
turned on, will overcome this. Where there is no reversing switch 
in the ignition circuit or where one cannot be used, attention to the 
points at regular intervals will prevent this effect from reaching a 
stage where most of the point has to be filed away to true it up. 

Q. In the use of the file, sandpaper, or emery cloth in this con= 
nection, just what is meant by truing the points up? 

A. Their surfaces must be made exactly parallel to one another 
so that when the points come together they touch uniformly over 
their entire surfaces. In the hands of the unskilled user, there is a 
tendency to bear dowm sidewdse wdth the file, thus forming rounded 
edges on the points. In addition to having the faces of the tw^o points 
l)erfectly parallel, the face of each point must be at right angles to its 
sides. Otherwise, there is bound to be unnecessary sparking between 
the points, and this causes them to burn away again much sooner. 
It is scarcely necessary to add that as little as possible of the metal 
should be removed. As long as there is enough of the platinum left 


728 


ELECTRICAL EQUIPMENT 


to make true parallel surfaces, the points need not be replaced if 
the means for adjustment permits utilizing them when worn far down. 

Q. What is the cause of the points freezing, or sticking, 
together? 

A. Permitting them to wear down to a point where they are in 
very poor condition and where the gap between parts of their surfaces 
causes the formation of a heavy arc, or hot flash of current, which 
practically welds them together. By giving them the necessary 
attention at regular intervals, this may be avoided. 

Q. How often should the contact points need attention? 

A. When new, they should run for a year or more without any 
attention. After they have been trued up, the succeeding interval 
will often depend upon the skill and care with which this has been 
carried out. 

Switches 

Q. How do switches as employed on the automobile differ 
in principle and operation? 

A. Starting-circuit switches are either of the knife-blade or 
the flat-contact type, while in the majority of cases the lighting 
switches are of the push-button type, though knife-blade switches 
are used for this purpose also. In some instances, one of the brushes 
of the machine is made to serve as a switch, as in the Delco. Ordi¬ 
narily, the switch is normally held open by a spring and is closed 
by foot pressure, the spring returning it to the open position as 
soon as released. A variation of this is the Westinghouse electro- 
magnetically operated switch in which a solenoid takes the place of 
foot operation. The circuit of the solenoid is controlled by a spring 
push button, which is normally held out of contact. Single-unit 
systems, such as the Dyneto, in which the machine automatically 
becomes motorized when the speed drops below a certain point, 
are controlled by a standard single-throw single-pole knife-blade 
switch which is left closed as long as the machine is running. 

Q. What faults may be looked for in switches? 

A. Loose connections; weakening of the spring; burning of 
the contact faces in the knife-blade type, due to arcing caused by 
releasing too slowly; dirt or other insulating substance accumulating 
on the contact faces of the flat-contact type; failure to release through 
binding. 


ELECTRICAL EQUIPMENT 


729 


Q. Why is it important to keep the switch contact faces clean 
and bright? 

A. Dirt or burned surfaces increase the resistance and cause 
a drop in the voltage at the starting motor. The energy represented 
by an electric current is a measure of the volume or amperes times 
the voltage or pressure under which it flows, and, as such low voltages 
are used, only a slight falling off represents a serious percentage 
of the total potential. With a dirty switch or one that makes poor 
contact, current that should be utilized in the starting motor is 
wasted in overcoming the resistance of the switch. 

Q. Why is it inadvisable to insert an extra switch in the start= 
ing circuit, as is done in some cases by owners to insure against 
theft? 

A. Because of the drop in voltage. The loss in switches as 
designed for lighting circuits is about 1 per cent, or a little over 1 
volt. If the same switch is used on the low voltage of the starter 
system, the loss is then equivalent to about 10 per cent. 

LIGHTING AND INDICATORS 
Lamps 

Q. How many types of bulbs are there in general use on 
automobiles? 

A. Four: miniature and candelabra screw base, and single- 
and double-contact bayonet-lock base, both of the latter being of 
the candelabra size. 

Q. Are these types equally favored? 

A. No. The screw-base type, particularly in the miniature 
size, will be found only on old cars, and this type, generally speaking, 
is practically obsolete on the automobile, as the vibration tends to 
unscrew the lamp. Of the bayonet-lock type, the single-contact 
style is steadily gaining favor. Ten million bulbs for automobile 
lighting were produced in 1915 (S.A.E. report) and of these 67 
per cent were of the single-contact type. 

Q. In how many different voltages are these bulbs made? 

A. Four: a 6—8-volt bulb for a 3-cell or 6-volt system; 12— 
16-volt bulb for 6-cell or 12-volt systems; and 18—24-volt bulbs for 
9-cell systems; 3—4-volt bulbs for tail-light and dash-light use, 
where these lights are burned in series on a 6-volt system, 


730 


ELECTRICAL EQUIPMENT 


Q. Are these the only voltages in which the bulbs are made? 

A. No. They are the types that are being standardized 
to reduce the stock of replacements that it is necessary for a garage 
to carry. It has been customary for the lamp manufacturer to 
supply bulbs made exactly for any voltage that the maker of the 
electric system ordered. Taking into consideration only the standard 
sizes now listed for use on 3-, 6-, and 9-cell systems, and the different 
bases regularly used, there are about twenty-four different bulbs 
that should be stocked by a garage. In addition, about forty other 
sizes are in general use, and if individual voltages had to be sup¬ 
plied, considering the different standard bases, a stock of over 
two-hundred different bulb sizes would be required. 

Q. Why is the voltage of a bulb expressed as “6—8”, “12— 
16”, etc.? 

A. Owing to the rise and fall of the battery voltage according 
to its state of charge, this variation must be provided for, or the 
lamps would be burned out wLen the battery was fully charged. 
Headlight bulbs for 3-cell systems are made for 6| volts, while the 
side, rear, and speedometer lights are made for 6J volts, owing to 
the lesser voltage drop in their circuits, but they will all operate 
satisfactorily on a potential that does not exceed 8 volts or does not 
drop below 6 volts. 

Q. When all the lamps burn dimly, what is the cause? 

A. The battery is nearly exhausted, in which case its voltage 
will be only 5.2 to 5.5 volts for a 3-cell system. The car should be 
run with as few lights as necessary to permit the generator to charge 
the battery quickly. 

Q. What is the cause of one light failing? 

A. Bulb burned out or its fuse blown; examine the fuse before 
replacing the bulb and if blown, examine the wiring before putting 
in a new bulb. Poor contact; see that the lamp is put in properly 
and turned to lock it in place. A double-contact bulb may have 
been put in single-contact socket, or vice versa. 

Q. Why will one lamp burn much brighter than the other? 

A. A replacement may have been made with a bulb of higher 
voltage; a 12-volt bulb will give only a dull red glow on a 3-cell 
system. Where the difference is not so marked as this, but still 
very perceptible, it may be due to the difference in the age of the 


ELECTRICAL EQUIPMENT 


731 


lamps. As a bulb grows old in service, its filament resistance 
increases, so that it does not take so much current and will not 
burn as brightly as when new. 

Q. Will the failure of a bulb cause its fuse to blow though 
there is no fault in its circuit? 

A. This sometimes happens owing to the breaking down of 
the filament, causing a short-circuit when the lamp fails. 

Q. Can the proper voltage bulbs needed for any system always 
be told simply by taking the total voltage of the battery, i.e., the 
number of cells times 2? 

A. No. Always examine the burned out bulb and replace 
with one of the same kind. Many 6-cell systems use 6-volt lamps 
and are known as 12—6-volt svstems. The batterv is divided into 

1 t/ 

two groups in series parallel for lighting and sometimes for charging, 
all the cells being in series for starting. Other arbitrary voltages 
are also adopted; for example, 14-volt bulbs are used on 12-cell 
systems, the battery being divided in the same manner, so that 
this would be a 24—12-volt system. The only safe way to order 
replacements is to give the voltage on the printed label on the old ■ 
bulb and state the make of the system on which it is to be used. 

Q. What type of bulb is used where the current is taken from 
the magneto, as on the Ford? 

A. As supplied by the maker, only the headlights are wired, 
and thev are in series, and in recent models a 9-volt bulb is used, 
but the above instructions for replacements will apply here also. 
Ordinarily, double-contact bulbs are required, unless the fixtures 
are insulated from one another, in which case the single-contact 
type can be used. 

Q. Why is a bulb of a voltage lower than that of the system 
itself often employed on 6=, 9=, and 12=cell systems? 

A. The lower the voltage, the thicker the filament can be made. 

A short com])aratively thick filament concentrates the light and 
makes the bulb easier to focus; it is also much more durable than 
the thin filament required for higher voltages. 

Q. Under what conditions will the best results be obtained 

from the head lamps? 

A. When the bulbs are in proper focus with the lamp reflectors. 
The usual focal length for headlight bulbs is if inch, and the 


I 


732 


ELECTRICAL EQUIPMENT 


focal length of the reflector is made greater than this to permit of 
adjustment. The center of the filament should be back of the focus 
of the reflector to spread the beam of light. In this position a 
greater number of the light rays are utilized and redirected by the 
reflector, producing a higher beam candlepower. If the center of 
the filament is forward of the focus, the lower part of the reflector 
will produce the most glare and throw it into the eyes of pedestrians 
and approaching drivers. 

Q. How can the headlights be focused? 

A. Place the car in position where light can be directed against 
a wall about 100 feet distant. Adjust the bulbs backward or forward 
until the spotlight on the wall is most brilliant and free from black 
rings and streaks. When this position is found, lock the bulb securely 
in place. Focus each headlight separately. See that the lamp 
brackets are set so that the light is being projected directly ahead. 

Q. How can metal headlight reflectors be cleaned when 
discolored? 

A. Wash by directing a gentle stream of cold water against 
the surfaces and allow to dry without touching them. The reflectors 
should never be rubbed with cloth or paper as it will scratch the 
highly polished surfaces. If they become very dull, it will be neces¬ 
sary to have them replated. 

Q. What is the meaning of the identification marks usually 
placed on bulbs, in addition to the voltage, such as “Q=6”? 

A. This refers to the size and shape of the bulb. The diameter 
of the glass bulb is expressed in eighths of an inch and its shape by 
a prefixed G for round (globular), T for tubular, S for straight- 
side, etc. Thus, G-6 is a round bulb f inch or f inch in diameter. 

Instruments 

Q. What instruments ordinarily are employed in connection 
with electric systems on the automobile? 

A. Either a double-reading ammeter, a volt-ammeter, or an 
indicator, the first named being employed generally. The ammeter 
shows whether the battery is charging or discharging or whether no 
current is passing; the indicator reads either Off or O71; while the 
voltammeter gives the voltage, usually upon pressing a button to 
put it into operation, in addition to the readings already mentioned. 


ELECTRICAL EQUIPMENT 


733 


Q. On what circuits are the indicating instruments placed? 

A. The charging circuit from the generator to the battery, 
and the lamp and ignition circuits. 

Q. Why is an ammeter not used for the starting=motor circuit? 

A. The current is so heavy and varies so greatly with the 
conditions that an ammeter designed to give an accurate reading 
of it would not be sensitive enough to indicate the smaller amounts 
of current used by the lamps, or produced by the generator for 
charging. Furthermore, the starting motor is intended only to 
be used for very short periods, while the other circuits are in 
constant use. 

Q. Do the small ammeters employed fail very often? 

A. Considering the unusually severe treatment to which they 
are subjected by the vibration and jolting of the car, their failure 
is comparatively rare, but as the conditions are so severe for a 
sensitive indicating instrument, too much dependence should not 
be placed on the ammeter reading when making tests. 

Q. What are the usual causes of failure? 

A. Failure to indicate—the generator, wiring, and other parts 
of the circuit being in good operative condition—may be caused by 
the pointer becoming bent, so as to bind it; the pointer may have 
been shaken off its base altogether by the jolting, or one of its connec¬ 
tions may have sprung loose from the same cause. 

Q. How can the ammeter reading be checked? 

A. By inserting the portable testing voltammeter in circuit 
with it, using the 30-ampere shunt and comparing the readings. 
The dash ammeter must not be expected to give as accurate a 
reading as the finer portable instrument. Failing the latter, a spare 
dash ammeter may be employed in the same manner and the spare 
may be tested beforehand by connecting to a battery of 4 dry cells 
in series; if brand new, they should give a reading of 18 to 20 amperes. 
Do not keep the ammeter in circuit any longer than necessary to 
obtain the reading, as it only runs the cells down needlessly. 

Q. Should an ammeter ever be used in testing the storage 

battery? 

A. No. Because it practically would short-circuit the battery, 
burn out the instrument, and damage the battery itself. Nothing 
but a voltmeter should be employed for this purpose, »as its high 


734 


ELECTRICAL EQUIPMENT 


resistance coil permits only a small amount of current to pass. An 
ammeter reading from a storage battery gives no indication whatever 
of its condition, whereas the voltage affords a close check on the 
state of charge, varying from 1.75 for a completely discharged cell 
to 2.55 volts for a fully charged one, the readings always being 
taken when the battery is either charging or discharging. The 
voltage on discharge will not be as high as on charge, the conditions 
otherwise being the same. 

Q. Why are indicators employed on some systems instead 
of ammeters? 

A. As the indicator is not designed to give a quantitative 
reading, it need not be so sensitive as an ammeter and accordingly 
can be made more durable. 

Q. What are the most frequent causes of failure of an indi= 
cator? 

A. Usually of a mechanical nature caused by the jolting, such 
as the target being shaken off its bearings, broken wire, etc. 

Q. When the engine is running slowly, and the ammeter or the 
indicator flutters constantly, going from “On” to “Off” at short inter= 
vals, in the case of the indicator, or from a small charging current to 
zero, in the case of the ammeter, what does this signify? 

A. That the setting of the battery cut-out is very sensitive 
and that the engine is then running at or about the speed that the 
instrument should cut-in. Since the speed of an engine varies con¬ 
siderably when running slowly, picking up momentarily and then 
falling off for a longer period, there is a corresponding variation in the 
potential, causing the cut-out to operate intermittently. This is a 
condition that seldom occurs and results in no harm when it does. 

Q. When the ammeter or indicator flutters in the same manner 
with the engine running at medium or at high speed, what does it 
indicate? 

A. That there is a loose connection between the generator and 
the cut-out, or an intermittent short-circuit or ground caused by a 
chafed wire alternately making contact with some metal part owing 
to the vibration. It is much more likely to be simply a loose connec¬ 
tion and will be found most often on the back of the cut-out itself. 
This should be remedied at once. If neglected, it will cause abnormal 
wear of the platinum points in the cut-out. 


ELECTRICAL EQUIPMENT 


735 


Q. When the ammeter does not indicate “Charge*^ though the 
engine is speeded up, but does register a discharge when the lights 
are turned on and the engine is idle, what is the nature of the trouble? 

A. Either the generator is not producing current or the regula¬ 
tor (where an external type is employed) is not working properly. 
The generator brushes may not be making proper contact with the 
commutator, or there may be a loose, corroded, or broken connection 
in the generator cut-out battery circuit. Where a belt drives the 
generator, it may be too loose to run the machine at its proper speed. 

Q. When the ammeter gives no charging indication though the 
lamps are off and the engine is speeded up, and gives no discharging 
indication though the engine is idle and lamps are switched on, what 
is likely to be the cause? 

A. There is an open or a loose connection in the battery circuit 
or in the battery itself. The ammeter may be at fault. See that its 
indicating pointer has not become jammed nor dropped off its bearings. 

Q. In case the ammeter indicates “Discharge’’ though the 
engine be idle and all lights turned off, what is the trouble? 

A. There is a short-circuit or a ground somewhere in the light¬ 
ing circuits or between the battery and the ammeter, as the discharge 
reading in such circumstances indicates a leakage of current; or the 
cut-out has failed to operate and still has the battery in circuit with 
the generator, though the engine is stopped. The ammeter pointer 
may be bent. 

Q. When the meter indicates a charge though the engine is at 
rest, what is the nature of the fault? 

A. The ammeter pointer has become bent or deranged so tliat 
it is stuck fast in place, showing a charge. 

Q. When the ammeter charge indications are below normal, 

what is apt to be the cause? 

A. The generator commutator or brushes may need attention, 
such as cleaning or sanding-in, or new brushes may be necessary. 
The generator speed may be too low; in case of belt drive, it may not 
be getting the benefit of the full speed of the engine owing to a slipping 
belt. The regulator (external type) may not be functioning properly, 
or there may be an excessive lamp load on the generator. 

Q. When the ammeter charge reading is above normal, what 

is likely to be the cause? 


ELECTRICAL EQUIPMENT 


73() 


A. There may be a short-circuited cell in the battery, or a short 
in the charging circuit, or the regulator (external type) may not be 
working properly. 

Q. What will cause the discharge reading of the ammeter to 
become abnormally high? 

A. The lamp load may be excessive, as where higher candle- 
power bulbs are used, or more lights than originally intended are put 
in the circuit. There may be leakage in some part of the lighting 
circuit, or the regulator contacts may be stuck together, permitting a 
discharge through it or through the generator. 

ELECTRIC QEAR=SHIFT 

Q. What is the operating principle upon which the electric gear= 
shifting mechanism is based? 

A. That of the solenoid and its attraction for its core when a 
current is passed through its winding. 

Q. What is the source of current supply for the electric gear¬ 
shift? 

A. The storage battery of the lighting system. The operation 
of gear-shifting is carried out so quickly that only a nominal additional 
demand is made on the batterv. 

Q. How is the electric gear-shift controlled? 

A. By a series of buttons corresponding to the various speeds 
and located on the steering wheel, and by a master switch. 

Q. What is the object of the buttons, and what are they termed? 

A. To partly close the circuit to the particular solenoid of the 
speed desired. They are termed “selector switches” since they per¬ 
mit selecting in advance the speed flesired. 

Q. Why is a master switch employed, and why is it so called? 

A. To avoid the complication which would otherwise result 
from the necessity of providing two switches for each change of speed, 
i.e., a selector swdtch and an operating switch. It is termed a master 
switch because it controls the current supply to all of the circuits. 

Q. Why is a neutral button provided in addition to the but= 
tons for the various speeds on the selector switch? 

A. To return anv of the selector buttons to neutral without 
the necessity of going through that speed in case it is not desired to 
engage the speed in question after the button has been pushed. Also 


ELECT RICA L EQ UI PM ENT 737 

to open any of the selector switches that may be closed when it is 
desired to stop. 

Q. What is the neutralizing device? 

A. It is a mechanism incorporated with the shifting mechanism 
to open the master switch automatically after the gears have been 
engaged. 

Q. Why is the neutralizing device necessary? 

A. If it were not provided, the master switch would remain 
closed, causing a constant drain on the battery and rendering the 
mechanism inoperative after one shift had been made. 

Q. How many solenoids are provided in the standard three= 
speed and reverse gear box? 

A. One for every movement necessary. 

Q. Is the current sent through a solenoid in one direction to 
pull the shifting bar into it and then in the opposite direction to move 
the bar the other way? 

A. No, the current is not reversed through the same solenoid. 
After the left-hand solenoid, operating the first-speed gear, for 
example, has pulled the shifter bar to the left, a second solenoid, 
on the opposite end of the same bar, is energized to pull it back to the 
right, to shift to second or intermediate. The current is sent through 
a different solenoid by means of the selector switches for each shift 
desired. 

Q. When the electric gear=shift failed to operate, where would 
be the most likely place to look for the cause of the trouble? 

A. First see that the battery is not exhausted, then that no 
connections between the battery and the terminal block have parted, 
thus cutting off the current supply. The wiring is so sim})le and so 
strongly protected that it is very unlikely to have anything happen to 
it except at the connections. This is likewise true of the solenoids. 

Q. In case the battery is amply charged and nothing is wrong 
with the connections, what procedure should be followed? 

A. Use the lamp-testing set described in connection with the 
lighting and starting systems and test out the various circuits as 
shown on the wiring diagram. In using this test, it must always be 
borne in mind that touching the two points to the same or connecting 
pieces of wire or metal will always cause the lamp to light. It is useful 
in this way for indicating the continuity of a wire, i.e., that it has not 


738 


KLECTKICAL EQUIPMENT 


broken under the insulation, but, until experience has been gained in 
its use, it will be nothing unusual to find that the points have been 
touched to connecting pieces of metal which have no relation to the 
circuit. As such metal will complete the circuit through the lamp, 
the latter will light, but without indicating anything of value to the 
trouble hunter. Always test the lamp itself before proceeding. It 
may have become partly unscrewed in its socket or its filament may 
have been broken. 

BATTERY 

Electrolyte 

Q. Why is it necessary to refill the battery jars at regular 
intervals? 

A. Because the heat generated in the cells evaporates the 
water from the electrolyte, and, if the latter is permitted to fall 
below the tops of the plates, they will dry out where they are 
exposed, and the heat of charging will then cause them to disinte¬ 
grate, ruining the battery. 

Q. Why should this be done at intervals of not less than 
two weeks? 

A. Because the limited amount of electrolyte permitted 
by the restricted size of the cells over the plates—usually one-half 
inch—will be evaporated in that period by a battery that is in 
more or less constant use. 

Q. Why should water alone and never acid or electrolyte 
be used to make up this loss? 

A. Only the water evaporates, so that if either acid or fresh 
electrolyte is added, it will disturb the specific gravity of the solu¬ 
tion in the cells and totallv alter their condition. 

Q. What is the reason that battery manufacturers insist 
that only distilled water or its nearest equivalent, rain water or 
melted artificial ice, be used for this purpose? 

A. Because ordinary water contains impurities that are 
apt to harm the plates, such as iron salts, or alkaline salts that will 
affect both the plates and the electrolyte. 

Q. What should be done to a battery that has had its efficiency 
impaired by being filled with impure water? 

A. The cells should be taken apart, the separators discarded, 
the plates thoroughly washed for hours in clean running water 


ELECTRICAL EQUIPMENT 


739 


without exposing them to the air where they would dry, the jars 
washed out, the plates reassembled with new separators, the jars 
filled with fresh electrolyte of the proper specific gravity, and the 
battery put on a long slow charge from an outside charging source, 
i.e., not on the car itself. Unless there are proper facilities for 
carrying this out, it will be preferable to ship the battery back to 
the maker so that it can be given proper treatment, particularly 
as it is necessary to reseal the cells. 

Q. How is electrolyte prepared? 

A. By adding pure sulphuric acid a very little at a time to 
distilled water until the proper specific gravity is reached, and then 
permitting the solution to cool before using. The mixture must 
always be made in a porcelain, hard rubber, or glass jar; never 
in a metal vessel. Commercial sulphuric acid or vitriol should 
not be employed, as it is far from pure. Never add acid to water. 
When the two are brought together, their chemical combination 
evolves a great amount of heat, and the acid will be violently 
spattered about. 

Q. How often should distilled or rain water be added to the 


cells? 

A. This will vary not alone with dift'erent systems but with 
different cars equipped with the same system, owing to the difference 
in conditions of operation. The only way to determine this definitely 
is to inspect the cells at short intervals and note how long they will 
operate before the electrolyte gets close enough to the tops of the plates 
to require additional water. This may be a week, ten days or two 
weeks, or even more, if the car is not run much. 

Q. When a battery requires the addition of water at very short 
intervals to keep the level of the electrolyte one=half inch above the 
plates, what does this indicate? 

A. It shows that the battery is being constantly overcharged, 
which keeps it at a high temperature, causing excessive evaporation. 
This will usually occur where a car is in constant use during the day 
but is driven very little at night. It may be remedied by adjustment 
of the regulation so as to reduce the output of the generator. Where 
this is not possible, as in the case of simple bucking-coil regulation 
which is entirely self-contained and permits no variation, additional 
resistance may be introduced in the generator-battery circuit. This 


740 


ELECTRICAL EQUIPMENT 


may take the form of a small-resistance unit consisting of German 
silver or other high-resistance wire wound on a porcelain tube and 
mounted on the forward side of the dash. A single-pole knife-blade 
switch should be placed in the circuit with the resistance so that 
the latter can be cut in or out of the generator circuit as circum¬ 
stances may require. 

Q. How can the amount of resistance to be inserted in the 
circuit be figured? 


A. By the use of Ohm’s law. In this case, it would be — = C 

or resistance divided by voltage equals current. How much resist¬ 
ance to use can only be answered by the conditions of operation. 
Where a car is used steadily during the day and very seldom at night, 
it may be necessary to reduce the charge by two-thirds. In the case 
of a 6-volt system normally charging at 12 amperes, this would 
require approximately 28 ohms additional, since -^- = 4 amperes. 
This is on the assumption that the battery actually receives 12 
amperes through the resistance of its original circuit. Seven is used 
as the voltage, since the generator of a 6-volt system generates current 
at 7 to 7| volts in order to overcome the voltage of the battery when 
fully charged. The amount of resistance wire necessary to give this 
resistance or any other resistance necessary may be found in tables 
of wire sizes and resistances of special wire employed for this purpose. 
The wire is bare and must be wound on the tube so that adjacent 
coils do not touch. An extreme instance is cited here. It may be 
necessary in many cases to reduce the charging rate by a very much 
smaller fraction. L^nless trouble of the nature mentioned is experi¬ 
enced, the charging rate should not be altered. 

Q. When the battery is constantly gassing, or “boiling’h 
as the car owner usually puts it, what is the trouble? 

A. It is being constantly overcharged. This will greatly reduce 
the life of the battery, and the charging rate should be reduced, as 
mentioned in the preceding answer. It is essential that the battery 
be kept fully charged; but if it is continually overcharged, this will 
keep the cells at an abnormal temperature which is injurious to the 
plates. The treatment to be given the battery will vary with the 
season, for the demand upon it is much heavier during cold weather 
than in summer. 



ELECTRICAL EQUIPMENT 


741 


Hydrometer Tests 

Q. Why should the battery be tested with the hydrometer 
at regular intervals of a week or so? 

A. Because the specific gravity of the electrolyte is the most 
certain indication of the battery’s condition. 

Q. What should the hydrometer read when the battery is 
fully charged? 

A. 1.280 to 1.300. 

Q. What point is it dangerous to permit the specific gravity 
of the electrolyte to fall below, and why? 

A. 1.250; because below this point, the acid begins to attack 
the plates and the battery plates sulphate. The lower the specific 
gravity, the faster sulphating takes place. 

Q. What should be done when the hydrometer reading is 
1.250 or lower? 

A. The battery should be put on charge immediately, either 
by running the engine or by charging from an outside source of 
current until the gravity reading becomes normal. 

Q. If the hydrometer reading of one cell is lower than that 
of the others, what should be done? 

A. Inspect the cell to see if the jar is leaking; note whether 
electrolyte is over the plates to the depth of ^ inch and whether 
the electrolyte is dirty. If these causes are not apparent, the cell 
will have to be opened and inspected for short-circuits from an accu¬ 
mulation of sediment in the bottom of the jar or from buckling of 
the plates. 

Q. Are hydrometer tests alone conclusive? 

A. No. To be strictly accurate, they should be checked by volt¬ 
age tests, in addition. 

Q. How should these voltage readings be taken? 

A. With the aid of a portable voltmeter, using the low-reading 
scale, i.e., 0-3 volts, and always with the battery discharging, the load 
not exceeding its normal low discharge rate. 

Q. Why should the test not be made with the starting=motor 

load? 

A. Because the discharge rate while the starting motor is being 
used is so heavy that even in a fully charged battery in good condition 
it will cause the voltage to drop rapidly. 


742 


ELECTRICAL EQUIPMENT 


Q. Why should the voltage readings not be taken while the 
battery is charging? 

A. Because the voltage of the charging current (always in 
excess of six volts) will cause the voltage of a battery in good condition 
to rise to normal or above the moment it is placed on charge, such 
readings are not a good indication of the battery’s condition. 

Q. What should the voltage of the cells be? 

A. In any battery in good condition, the voltage of each cell at 
the battery’s normal low discharge rate (5 to 10 amperes, as in carry¬ 
ing the lamp load) will remain between 2.1 and 1.9 volts until it begins 
to approach the discharged condition. A voltage of less than 1.9 volts 
per cell indicates either that the battery is nearly discharged or that 
it is in bad condition. The same state is also indicated when the 
voltage drops rapidly after the load has been on a few minutes. 

Joint Hydrometer=Voltmeter Test 

Q. What should the hydrometer and voltmeter readings be for a 
fully charged battery in good condition? 

A. Hydrometer 1.275 to 1.300; voltage 2 to 2.2 volts per cell. 

Q. What does a hydrometer reading of 1.200 or less with a 
voltage of 1.9 volts or less per cell indicate? 

A. This shows that excess acid has been added to the electro¬ 
lyte. Under these conditions, the lights will burn dimly even though 
the hydrometer test alone would appear to show that the battery is 
more than half charged. 

Q. What does a hydrometer reading in excess of 1.300 indicate? 

A. It indicates that an excessive amount of acid has been added 
to the electrolyte, regardless of whether the voltage reading is high, 
low, or normal. 

Q. Where a low voltage reading is found, how can it be deter= 
mined whether the battery is in bad condition or merely discharged? 

A. Stop the discharge by switching off the load (lamps) and put 
the battery on charge, cranking the engine by hand. After a few 
minutes of charging, note whether the voltage of each cell promptly 
rises to 2 volts or more. Any cells that do not are probably short- 
circuited or otherwise in bad condition. 

Q. How can a rough test of the condition of the battery be made 
without the use of any instruments? 


ELECTRICAL EQUIPMENT 


743 


A. On systems fitted with a battery cut-out in the generator 
battery circuit, remove the cover of the cut-out (the generator being 
stationary) and momentarily close the cut-out points with the finger. 
The discharge shown by the ammeter the monent the points are 
closed should be anywhere from 10 to 20 amperes, differing, of 
course, with different systems. In any case, it should be equal to or 
greater than the maximum normal output of the generator, provided 
the battery is at least three-quarters charged. 

Q. What effect will allowing the electrolyte to fall too low in 
the cells have, apart from the damage that it will cause to the plates? 

A. It will tend to increase the voltage if the battery is otherwise 
in good condition, and this may be carried to a point where it will 
burn out the lamps. 

Q. What is meant by “floating the battery on the line’^? 

A. This describes the relation of the battery to the generator 

and lighting circuits in systems where the current for lighting is taken 

; 

directly from the generator when running, any excess over the require¬ 
ments of the lamps being absorbed by the battery. The moment the 
generator speed falls below the point where it supplies sufficient cur¬ 
rent to supply all that is needed for the lamps, the battery automati¬ 
cally supplies the balance. When the generator is idle, the battery, 
of course, supplies the current for lighting as well as for starting. 

Gassing 

Q. Why should the cell tops be wiped dry from time to time 
and the latter as well as the terminals be washed with a weak 
solution of ammonia and water? 

A. As the charge approaches completion, the cells gas; when 
overcharged they gas very freely. This gas carries with it in the 
form of a fine spray some of the electrolyte, and the acid of the latter 
will attack the terminals and corrode them. Wiping clean does 
not remove this acid entirely, so the ammonia solution is necessary 
to counteract its effect, the ammonia being strongly alkaline. 

Q. Why should an unprotected light, i.e., any flame or spark, 
not be allowed close to a storage battery? 

A. Because the gas emitted by the battery on charge is hydro¬ 
gen, which is not only highly inflammable but, when mixed in 
certain proportions with air, forms a powerful explosive mixture. 


744 


ELECTRICAL EQUIPMENT 


Q. What is the cause of gassing? 

A. When a battery is charged, the water of the electrolyte 
is decomposed by the current into gases. During the early part 
of the charge these gases unite with the active material of the plates, 
but as the charge proceeds, more gas is evolved than the plates 
can take care of and it bubbles up through the electrolyte. This 
is known as the gassing point, and the temperature of the cell also 
begins to rise at that point. 

Q. Is gassing harmful to the battery? 

A. The greatest wear on the positive plates takes place during 
the gassing period, and, if carried too far, they may be injured by 
reaching a dangerous temperature (105° F., or over) which will tend 
to loosen the active material. 

Q. How can gassing be checked? 

A. By cutting down the charge. In some systems this can 
be effected by the insertion of extra resistance provided for the 
purpose. Where this cannot be done and it is necessary to keep 
the car running, turn on all the lamps or start the engine once or 
twice to reduce the charge of the battery. As the lamps usually 
consume 80 to 95 per cent of the generator output, they should be 
sufficient to prevent a further overcharge. 

Q. Can the generator be disconnected from the battery to 
prevent overcharge? 

A. Not unless it is short-circuited, as directed in the instruc¬ 
tions covering different systems. Otherwise, it will blow its field 
fuse or, where one is not provided, burn out its windings, except 
in cases where special provision is made to guard against this. 

Sulphating 

Q. Why must a battery never be allowed to stand in a fully dis= 
charged state? 

A. Because the acid of the electrolyte then attacks the plates 
and converts the lead into white lead sulphate which is deposited 
on them in the form of a hard coating that is impenetrable to the 
electrolyte, so that the plates are no longer active. The battery 
then is said to be sulphated. 

Q. Can a sulphated battery be put in good condition, and what 
treatment must be given it to do so? 


ELECTRICAL EQUIPMENT 


745 


A. If the sulphating has not gone too far, the battery may 
be brought back to approximately normal condition by a long heavy 
charge at a higher voltage than ordinary. Where the battery has 
become badly sulphated, it is preferable to remove it from the car 
and charge from an outside source of current, as it may require 
several days to complete the process. (Note instructions regarding 
the running of the generator when disconnected from the battery, 
as otherwise it may be damaged.) If avoidable, the car should not 
run with the battery removed. If the battery has not stood dis¬ 
charged for any length of time, the charge may be given on the 
car by running steadily for 8 to 10 hours with all lights off. No 
lamps must be turned on, as the increased voltage is liable to burn 
them out. 

Voltage Tests 

Q. What is the purpose of the voltmeter in connection with the 
battery? 

A. It is chiefly useful for showing whether a cell is short- 
circuited or is otherwise in bad condition. 

Q. Can the voltmeter alone be relied upon to show the condition 
of the cells? 

A. No; like the hydrometer, its indications are not always con¬ 
clusive, and it must be used in conjunction with the hydrometer to 
insure accuracv. 

Q. What type of voltmeter should be employed for making 
these tests? 

A. For garage use, a reliable portable instrument with several 
connections giving a variable range of readings should be employed. 
For example, on the 0-3 volt scale, only one cell should ever be tested; 
attempting to test any more than this is apt to burn out the 3-volt 
coil in the meter. The total voltage of the number of cells tested 
should never exceed the reading of the particular scale being used at 
the time, as otherwise the instrument will be ruined. 

Q. Must these readings be particularly accurate? 

A. Since a variation as low as .1 volt (one-tenth of a volt) makes 
considerable difference m what the reading indicates as to the condi¬ 
tion of the battery, it will be apparent that the readings must not only 
be taken accurately, but that a cheap and inaccurate voltmeter is 
likely to be misleading rather than helpful. 


746 


ELECTRICAL EQUIPMENT 


Q. What precautions should be taken before using the volt= 
meter? 

A. Always see that the place on the battery connector selected 
for the contact is bright and clean and that the contact itself is firm, 
otherwise the reading will be misleading since the increased resistance 
of a poor contact will cut down the voltage. 

Q. How is the instrument connected to the battery? 

x\. The positive terminal of the voltmeter must be brought in 
contact with the positive terminal of the battery and the negative 
terminal of the voltmeter in contact with the negative terminal of 
the battery. 

Q. In case the markings on the battery are indistinct, how can 
the polarity be determined? 

A. Connect the voltmeter across any one cell. Should the 
pointer not give any voltage reading, butting against the stop at the 
left instead, the connections are wrong and should be reversed; if the 
instrument shows a reading for one cell, the positive terminal of the 
voltmeter is in contact with the positive terminal of the battery. 
This test can be made without any risk of short-circuiting the cell, 
since the voltmeter is wound to a high resistance and will pass very 
little current. Such is not the case with the meter, which should 
never be used for this purpose. 

Q. When the battery is standing idle, what is the cell voltage 
and why is this not a good test? 

A. Approximately two volts, regardless of whether the battery 
is fully charged or not. Voltage readings taken when the battery is on 
open circuit, i.e., neither charging nor discharging, are only of value 
when the cell is out of order. 

Q. If the battery is in good condition and has sufficient charge, 
what should the voltmeter reading show? 

A. Losing the lamps for a load, the voltage reading after the load 
has been on for five minutes or longer should be but slightly lower 
(about .1 volt) than if the battery were on open circuit. 

Q. When one or more cells are discharged, what will the read= 
ing show? 

A. The voltage of these cells will drop rapidly when the load is 
first put on and sometimes even show reverse readings, as when a cell 
is out of order. 


ELECTRICAL EQUIPMENT 


747 


Q. What will the voltmeter indicate when the battery is nearly 
discharged? 

A. The voltage of each cell will be considerably lower than if on 
open circuit after the load has been on for five minutes or more. 

Q. How can the difference be distinguished between cells that 
are merely discharged and those that are in bad condition? 

A. Put the battery on charge, cranking the engine by hand to 
start, and test again with the voltmeter; if the voltage does not rise to 
approximately 2 volts per cell within a short time, it is evidence that 
there is internal trouble which can be remedied only by dismantling 
the cell. 

Q. What effect has the temperature on voltage readings? 

A. The voltage of a cold battery rises slightly above normal on 
charge and falls below normal on discharge. This last is one of the 
chief reasons for its decreased efficiency in cold weather. 

Q. What is the normal temperature of the battery and to what 
does this refer? 

A. The normal temperature of a battery is considered at 70° F., 
but this refers to the temperature of the electrolyte in the battery as 
shown by a battery thermometer and not to the temperature of the 
surrounding air. If the battery has been charging at a high rate for 
some time, it may be normal even though the weather be close to zero 
at the time. 


Sediment 

Q. What is the cause of sediment or mud accumulating 
in the jars, and why must it be removed before it reaches the bottoms 
of the plates? 

A. This sediment consists of the active material of the plates, 
which has been shaken out, due to the loosening caused by the charg¬ 
ing and discharging, and aggravated by the constant vibration. It 
must never be allowed to reach the plates, as it is a conductor and 
will short-circuit them and thus ruin the battery. 

Q. How long will a battery stay in service before this occurs? 

A. This depends on the type of jar employed and the treat¬ 
ment that the battery has received. If it has been kept constantly 
overcharged, or if discharged to exhaustion m a veiy shoit period, 
as by abuse of the starting motor when the engine is not in good 


748 


ELECTRICAL EQUIPMENT 


starting condition, or if it has been subjected to short-circuits by 
grounding or by dropping tools on its terminals, the plates will 
disintegrate much quicker than where proper treatment has been 
given it. With the old-style jar, only an inch or so is allowed to 
hold this accumulation of sediment below the plates, while in later 
types fully 3 inches or more are allowed in the depth of the cell for 
this purpose. A battery with jars of the latter type that has been 
cared for properly should not require washing out under two years. 
The procedure is the same as that given for removing the effects of 
impure water. The plates must never be allowed to dry. 

Washing the Battery 

Q. What is meant by washing the battery, and why is it 
necessary? 

A. Washing a battery involves cutting the cells apart, wash¬ 
ing the elements and the jars, and reassembling with new separators 
and new electrolyte. It is necessary to prevent the accumulation 
of sediment, consisting of active material shaken from the plates, 
to a point where it will touch them and thus cause a short-circuit. 

Q. How often is it necessary to wash a battery? 

A. This will depend on the type of cell in the battery and the 
age of the latter. If the battery has the modern-style jar with extra 
deep mud space, it probably will not be necessary to wash it 
until it has seen two to three seasons’ use. With the older form 
of cell in which the space allowed for sediment is much less, washing 
doubtless will be necessary at least once a season. As the batter}' 
ages, it will be necessary to wash it oftener. 

Q. What other causes besides the type of jar and the age of 
the battery influence the frequency with which it is necessary to 
wash the battery? 

A. The treatment the battery has received. If it has been 
abused by overcharging and permitting the cells to get too hot, 
the active material will be forced out of the grids much sooner. 

Q. How can the necessity for washing be determined? 

A. The presence of one or more short-circuited cells in a 
battery that has not been washed for some time will indicate the 
necessity for it. Each cell should be tested separately with the 
low-reading voltmeter; a short-circuited cell will either give no 


ELECTRICAL EQUIPMENT 


749 


voltage reading or one much below that of the others. Cut such 
a cell out and open it; if the short-circuit has been caused by an 
accumulation of sediment, the others most likely are approaching 
the same condition. 

Q. How is a battery washed? 

A. By cutting the cells apart, unsealing them, and lifting out 
the elements which should be immersed immediately in a wooden 

K' 

tub of clean pure water. The separators then are lifted out and 
the positive and negative groups of plates separated, but they must 
be marked so that the same groups may go back in the right cells. 
Before disposing of the old electrolyte, its specific gravity should 
be noted, as new electrolyte of the same density must be used. 
The plates should be washed in copious running water for several 
hours, but their surfaces must never be exposed to the air. Reas¬ 
semble with new separators, fill the jars with fresh electrolyte of 
the same specific gravity as that discarded, and keep the elements 
under water until ready to place in the jars, which then should be 
sealed and the lead connectors burned together again. 

Give a long slow charge after reassembling. The battery will 
not regain its normal capacity until it has been charged and dis¬ 
charged several times. 


Connectors 

Q. Why should lead connectors be employed, and why is 
it necessary to burn them together? 

A. Any other metal will corrode quickly. Burning is necessary 
to make good electrical connection, except where bolted connectors 
are employed. 

Q. When connections have become badly corroded or broken, 

what should be done with them? 

A. They should be replaced with new lead-straj) connectors 
supplied by the makers. If they are not obtainable and the battery 
must be in service meanwhile, the old ones can be cleaned b\ cutting 
awav the corroded parts and burning new lead on them to biiiig 
them to normal size. If broken, burn together with lead in the 
same way. Heavy copper cable can be used temporarily but must 
be removed as soon as possible, as it will corrode quickly. Never 
use any other metal except lead or copper and never use light copper 


750 


ELECTRICAL EQUIPMENT 


wire. It will either be burned up in a flash or it will cut down the 
amount of current from the battery, thus causing unsatisfactory 
operation. 

Buckled Plates 

Q. What is the cause of badly disintegrated or buckled plates? 

A. Sudden discharge due to a short-circuit or to constant 
abuse of the starting motor on an insufficiently charged battery. 

Q. Is there any remedy for such a condition? 

A. If the plates are not badly buckled and have not lost much 
of their active material, the cells may be put in service again by 
washing and reassembling as described, but if there is any con¬ 
siderable loss of active material, new plates will be necessary. 

Low Battery 

Q. What are the indications of a low battery? 

A. The starting motor fails to turn the engine over, or does so 
very slowly, or only a part of a revolution. The lights burn very dimly. 
The hydrometer shows a specific-gravity reading of 1.250 or less. 
\Oltrneter test shows less than 5 volts for a 3-cell battery (for greater 
number of cells, in proportion), or 1.75 volts or less for each cell. 

Q. What are the causes of a low battery? 

A. The electrolyte not covering the plates, or being too 
weak or dirtv. A short-circuit in the batterv due to the accumulation 
of sediment reaching the bottom of the plates. An excessive lamp 
load, all lights being burned constantly with but little daylight 
running the car. Generator not charging properly. 

Specific Gravity; Voltage 

Q. What are the specific gravity and voltage of fully discharged 
and fully charged cells? 

A.' Total discharge: 1.140 to 1.170 on the hydrometer; and 1.70 
to 1.85 volts on the voltmeter. Fully charged: 1.276 to 1.300 specific 
gravity; 2.35 to 2.55 volts. 

Q. Are these readings always constant for the same conditions? 

A. No. The charging voltage readings will vary with the 
temperature and the age of the cell; the higher the temperature 
and the older the cell the lower the voltage will be. Hydrometer 


ELECTRICAL EQUIPMENT 


751 


readings also depend on the temperature to some .extent. For 
every ten degrees Fahrenheit rise in temperature, the specific gravity 
reading will drop .003 or three points, and mce versa. 

Q. Under what conditions should voltage tests be made? 

A. Only when the battery is either charging or discharging. 
Readings taken when the battery is idle are of no value. 

Q. Under what conditions should hydrometer tests be made? 

A. The electrolyte must be half an inch over the plates and 
it must have been thoroughly mixed by being subjected to a charge. 
Hydrometer readings taken just after adding water to the cells 
are not dependable. 

Q. When should acid be added to the electrolyte? 

A. As the acid in a battery cannot evaporate, the electrolyte 
should need no addition of acid during the entire life of the battery 
under normal conditions. Therefore, if no acid has leaked or splashed 
out and the specific gravity is low, the acid must be in the plates 
in the form of sulphate and the proper specific gravity must be 
restored by giving the battery an overcharge at a low charging rate. 

Q. What does a specific gravity in some cells lower than 
in others indicate? 

A. Abnormal conditions, such as a leaky jar, loss of acid 
through slopping, impurities in the electrolyte, or a short-circuit. 

Q. How can it be remedied? 

A. Correct the abnormal conditions, and then overcharge 
the cells at a low rate for a long period, or until the specific gravity 
has reached a maximum and shows no further increase for 8 or 10 
hours. If, at the end of such an overcharge, the specific gravity is 
still below 1.270, add some specially prepared electrolyte of 1.300 
specific gravity. Electrolyte should not be added to the cells under 
any other conditions. 

Q. Is an overcharge beneficial to a battery? 

A. The cells will be kept in better condition if a periodical 
overcharge is given, say once a month. This overcharge should 
be at a low rate and should be continued until the specific gravity 
in each cell has reached its maximum and comparative readings 
show that all are alike. To carry this out properly will require 
at least 4 hours longer than ordinarily would be necessary for a 
full charge. If the plates have become sulphated due to insufficient 


7.52 


ELECTRICAL EQUIPMENT 


charging, it may be necessary to continue the overcharge for 10 to 
15 hours longer. Should the specific gravity exceed 1.300 at the 
end of the charge, draw off a small amount of electrolyte with the 
syringe from each cell and replace with distilled water. If below 
1.270, proceed as mentioned above for addition of acid. 

Charging from Outside Source 

Q. What is meant by charging from an outside source? 

A. A source of direct current other than the generator on 
the car. 

Q. Why is it necessary to charge the battery from an outside 
source? 

A. When the battery has become sulphated, has been standing 
idle for any length of time, or has been run down from any other 
cause so that it is out of condition, a long charge at a uniform rate 
is necessary, and it would seldom be convenient to run the car for 
8 or 10 hours steadily simply to charge the battery; frequently, a 
longer charging period than this is necessary. 

Q. How is charging from an outside source effected? 

A. This will depend upon the equipment at hand and the nature 
of the supply, i.e., whether alternating or direct current. If the 
current is alternating, a means of converting it to direct current is 
necessary, such as a motor-generator, a mercury-arc rectifier, chemi¬ 
cal or vibrating type of rectifier. These are mentioned about in the 
order of the investment involved. In addition, a charging panel is 
needed to complete the equipment, this panel being fitted with 
switches, voltmeter, and ammeter, and a variable resistance for regu¬ 
lating the charge. Where direct-current service is obtainable at 110 
or 220 volts, the rectifier is unnecessary. 

Q. How can a battery be charged from direct=current service 
mains without a special charging panel? 

A. By inserting a double-pole single-throw switch and 10- or 15- 
ampere fuses on taps from the mains and ordinary incandescent 
lamps in series with the battery to reduce the voltage. Fig. 480. 

Q. How many lamps will be needed? 

A. This will depend upon their character and size, as well 
as upon the amount of charging current necessary. For a 10-ampere 
charge for a G-volt storage battery, seven 110-volt 100-watt (32 


ELECTRICAL EQUIPMENT 


753 


2 


2S 


c. p.) carbon-filament lamps, or their equivalent, will be needed • 
I. e. fourteen 110-volt 50-watt (16 c.p.) carbon-filament lamps;’ 
eighteen 110-volt 40-watt tungsten lamps, or twenty-eight 110-volt 
25-watt tungsten lamps. For a 
12-volt or 24-volt battery the number 
of lamps will have to be decreased 
in proportion in order not to cut the 
voltage of the supply current below 
that of the battery. For 220-volt 

d. c. supply mains, if a three-wire 
system is employed, the taps should 
be taken from the center wire and 
one outside wire; this will give 110 
volts. If the service is 220-volt two- 
wire, more lamps will be needed to 
reduce the voltage, which should 
exceed that of the battery by only IJ 
to 2 volts, except where a high volt¬ 
age charge to overcome sulphating 
is being given, in which case it may 
be slightly higher. 

Q. Where no outside source 
of current is available, or where no 
rectifier is at hand to convert alter¬ 
nating current, how can the battery 
be given the long charge necessary? 

A. Run the engine. Supply it 
with plenty of oil and provide hose 
connections from the water supply 
to the filler cap on the radiator and 
a drain from the lower petcock. 

Open the latter and turn on just 
sufficient water to keep the engine 
reasonably cool; increase if necessary 
as it runs hotter. 

Q. What precaution must be taken always before putting the 
battery on charge from an outside source? 

A. The polarity of the circuit must be tested in order to 



Fig. 480. Diagram of Connections for 
Charging Six-Volt Storage Battery 
from Lighting Circuit 

































754 ELECTRICAL EQUIPMENT 

make certain that the battery will be charged in the proper 
direction. 

Q. How can this be done? 

A. If a suitable voltmeter is at hand, i.e., one of the proper 
voltage for the 110-volt current, connect it to the mains. If the 
needle does not move over the scale but shows a tendency to butt 
against the stop pin at the left, reverse the connections. The needle 
will then give a proper reading and the positive connection to the 
meter must be used for the positive side of the battery. Should no 
voltmeter of the right voltage be available, connect two short wires 
with bared ends to the fused end of the switch. Dip the bared ends 
of the wire in a glass of water, being careful to keep them 
at least an inch apart. When the switch is closed, fine bubbles 
will be given off by the wire connected to the negative side. The 
battery terminals are stamped Pos. and Neg., and the connec¬ 
tions should be made accordingly. 

Intermittent and Winter Use 

Q. What should be done with an idle battery? 

A. If it is to be idle for any length of time, as where the car 
is to be stored, it should be given a long overcharge as described 
above before being put out of service. Fill the cells right to the top 
with distilled water to allow for evaporation and absorption of 
acid by the plates. Give the battery a freshening charge at a low 
rate once a month. Discharge the battery and re-charge before 
putting it into service again. If it has stood out of service for a 
long period, the battery will be found at a low efficiency point and 
will not reach its maximum capacity again until it has had several 
charges and discharges. 

Q. Does cold weather have any effect on the storage battery? 

A. It causes a falling off in its efficiency. If not kept charged, 
the electrolyte will freeze under the following conditions: battery 
fully discharged, sp. gr. 1.120, 20° Fahrenheit; battery three-quarters 
discharged, sp. gr. 1.160, temperature zero; half discharged, sp. gr. 
1.210, 20 degrees below zero; one quarter discharged, sp. gr. 1.260, 
60 degrees below zero. When storing away for the winter, the bat¬ 
tery must either be kept charged or put where the temperature 
does not go lower than 20 degrees above zero. 


INDEX 


PAGE 


A. c. rectifiers. 673 

Ammeter . 546 

Ammeter and dash lamp. 570 

Armature windings. 38 

Atwater Kent ignition system.. . . 172 
Anbnrn-Delco Aviring diagram.... 322 

Anto-Lite system. 334 

Automatically timed systems. 138 

Eisemann centrifugal-governor 

type. 139 

Herz ball-governor type. 140 

Automatic battery cut-out. 284 

Adlake type. 285 

Ward-Leonard type. 285 

Automatic engagement. 297 

Auto-Lite type. 297 

Bosch-Eushmore type. 297 

B 

Back-kick releases . 300 

Batteries . 53 

Battery and wiring, Fisher. 577 

Battery, capacity. 629 

Battery, care of. 632 

a. c. rectifiers. 673 

adding acid. 633 

adding distilled Avater. 632 

adjusting specific gravity. 638 

care of battery in AAunter. 675 

charging from outside source.. . 669 
charging in series for economy. 672 

cleaning battery. 651 

cleaning repair parts. 689 

<letecting deranged cells. 649 

equalizing charges necessary. . . 671 

gassing. 641 

higher charge needed in cold 

Aveather. 643 

how to take readings. 649 

hydrometer. 633 

installing neAv battery. 667 

internal damage. 648 

joint hydrometer and voltmeter 

tests.650, 687 

lead burning. 661 

methods of charging. 672 

motor-generator . 673 

overhauling battery. 655 

replacing jar. 652 

restoring sulphated battery. . . . 646 

specific gravity too high. 647 

sulphating . 644 


PAGE 

Battery, care of (continued) 


temperature variations in volt¬ 
age test .. 650 

to test rate of charge. 681 

to test rate of discharge. 678 

Amltage tests . 685 

Avhy starting is harder in cold 

AA^eather . 676 

Battery cell on charge. 627 

Battery cell on discharge. 628 

Battery construction . 631 


Battery ignition systems, typical 

arrangements. 171 

Atwater Kent system. 172 

Connecticut battery system. . .. 175 

Delco system . 181 

Remy system. 178 

Westinghouse ignition unit. . . . 171 
Battery imjAortant in starting and 

lighting . 623 

Bijur system. 343 

Bosch-Eushmore system. 360 

Brushes . 46 

Buick-Delco type Aviring . 318 


C 

Cells of storage battery, parts of. 625 


electrolyte . 626 

elements. 625 

separators . 626 

Chain-driven Genemotor . 532 

mounting starter . 532 

operation . 536 

Aviring . 535 

Chevrolet-Auto-Lite type, two- 

Avire system. 322 

Choker, or priming-rod, assembly. 569 

Circuit-breaker.286, 325 

Circuits.11, 33 

multiple or shunt. 13 

series . 12 

series-multiple . 13 

Clutches . 298 

necessity for disengaging device 298 

roller type. 300 

Coils and Aubrators. 90 

complication of multi-vibrator. 91 

function of coil. 90 

master vibrator. 91 

necessity for vibrator. 90 

non-Aubrator coil. 92 



















































































756 


INDEX 


PAGE 

Commutator. 35 

Commutator maintenance. 400 

Condensers.29, 94 

Conductors.8, 10 

Connecticut battery system. 175 

automatic switch. 178 

Constant-current generator. 275 

slipping-clutch type. 270 

Constant-potential generators .... 280 

“ built-in ” regulation type. 281 

external regulator type. 282 

Contact makers or timers. 89 

Atwater Kent interrupter. 89 

roller contact timer. 89 

Control. 515 

battery cut-out. 515 

Delco . 308 

Splitdorf . 488 

switch. 510 

Westinghouse. 521 

Counter e. m. f. 50 

Current 

chemical effect of. 19 

chemical sources of. 80 

Current and volume. 31 


PAGE 

Dynamotor.51, 487, 507 

Delco. 307 

Dyneto . 411 

North East. 452 

Westinghouse. 521 

Dyneto system. 411 

E 


Electric circuit. 3 ' 

chemical effect of current. 19 

circuits. 11 

conductors . 8 

current . 3 

electrical pressure. 4 

heating effect of current. 18 

non conductors. 10 

Ohm’s law. 5 

power unit. 0 

resistance . '5 

short-circuits and grounds. 15 

size of conductors. 10 

voltage drop . 9 

Electric current . 3 

Electric gear-shift. 014 


D 


Delco ignition system. 182 

Delco ignition relay.185, 187 

earlier model interrupter. 182 

interrupter for higher speed en¬ 
gines . 180 

timer with resistance unit. 183 

Delco instructions. 388 

adjusting third brush. 389 

commutator maintenance. 400 

seating brushes. 398 

testing armatures. 401 

testing circuit-breaker. 397 

testing cut-out . 394 

testing field coils. 400 

tests of wiring. 390 

Dimming devices. 312 

Disco instructions. 411 

Disco system. 411 

Disco units. 411 

Distributor. 93 

Dixie magneto. 112 

circuits; essential elements. . .. 112 

timing. 114 

Double-spark ignition. 124 

Driving connections for transmis¬ 
sion and regulation. 290 

Dual ignition system. 118 

Bosch type. 118 

details of typical distributor. . . 121 

Remy type. 120 

typical wiring diagram. 122 

Duplex ignition system. 123 


from first to intermediate or 


high . 019 

general plan. 614 

principle of action. 614 

starting first speed. 616 

stopping car. 616 

wiring. 620 

Electric horns. 307 

Electric motor principles. 47 

batteries. 53 

counter e. m. f. 50 

dynamotors . 51 

theory of operation. 47 

types of motors. 50 

Electric starting and lighting sys¬ 
tems . 269 

analysis of types. 315 

fundamental characteristics . . . 269 

general features . 270 

electric gear-shift. 614 

installing special systems for 

Ford cars. 531 

lighting. 309 

methods of regulation.. 275 

practical analysis of types. 315 

protective devices. 284 

standardization . 286 

starting and lighting storage 

batteries. 624 

starting motors. 287 

transmission and regulating de¬ 
vices . 293 

Electrical devices, inherent weak¬ 
ness of . 1 





































































































INDEX 


757 


PAGE 


PAGE 


Electrical equipment for gasoline 

cars. 

electric starting and lighting 

systems . 269 

elementary electrical principles. 2 

ignition. 81 

Electrical pressure. 4 

Electricity on automobiles, impor¬ 
tance of. 1 

Electromagnets . 22 

Elementary dynamo. 34 

Elementary electrical principles. . 2 

F 

Failure of engine to start in shaft- 


drivmn Genemotor. 546 

Faulty ignition. 1 

Field magnets. 40 

forms of. 46 

permanent field. 40 

self-excited fields . 43 

Firing order. 143 

firing orders and ignition ad¬ 
vance . 147 

magneto mounting. 167 

possible combinations . 145 

typical firing order. 143 

wiring. 162 

Fisher starting-lighting system 

for Ford cars. 574 

battery and wiring. 577 

mounting starting unit. 575 

operating instructions. 579 

preparing engine. 574 

Ford magneto. 124 

misfiring. 128 

current supply and distribution. 127 

Ford-starter installations. 531 

Fisher . 574 

general instructions. 531 

Genemotor. 532 

Gray & Davis. 546 

Heinze-Springfield . 559 

North East . 579 

Splitdorf . 586 

Westinghouse . 594 

Friction and resistance. 31 

Fuses.305, 327 


G 


Genemotor . 

chain-driven type. 

shaft-driven type. 

Generator design follows magneto 

precedent.. 

Generator output, control of, nec¬ 
essary . 

Generator principles. 

armature windings. 


532 

532 

537 

169 

275 

34 

38 


Generator principles (continued) 


brushes. 46 

classification of. 34 

commutators . 35 

elementary dynamo . 34 

field magnets. 40 

Generator starting motor. 493 

Generators 

Auto-Lite . 334 

Bosch-Eushmore . 279 

Delco .278, 383 

Dyneto . 412 

Gray & Davis. 416 

Heinze-Springfield . 435 

Leece-Neville. 443 

Eemy . .. 467 

Wagner . 515 

Westinghouse . 277 

Gray & Davis. 546 

installation . 546 

instructions . 557 

testing generator with ammeter 559 

Gray & Davis service tests. 427 

generator test chart. 428 

starting-motor test chart.432 

to adjust cut-out. 433 

to adjust regulator. 435 

Gray & Davis system. 416 


H 

Handy test set. 328 

Headlight glare . 312 

Heating effect of electric current. 18 
Heinze-Springfield starting-lighting 

system .435, 559 

ammeter and dash lamp. 570 

choker, or priming-rod, assembly 569 

installing battery. 569 

installing unit. 562 

preliminary operations. 559 

switch and wiring. 565 

tail and side lights, horn, etc.. . 570 

testing and operation. 572 

High-tension magneto. 105 

High-tension system. 84 

Hydraulic analogy in ignition sys¬ 
tem . 

current . 

office of condenser., • 100 

transformer. 101 

Hydrometer . 033 

frozen cells . 037 

hydrometer tests. 035 

low cells. 038 

variations in readings. 036 

I 

Ignition 

fundamental ignition principles 1 
ignition systems .. 118 

































































































758 


INDEX 


PAGE 


Iguitiou (continued) 
modern battery ignition systems 169 

sources of current. 86 

spark timing. 129 

testing, adjustment, and main¬ 
tenance . 192 

Ignition methods, changes in. 88 

Ignition setting point. 141 

Ignition systems. 118 

Ignition-system timing point. 138 

Incandescent lamps . 309 

Bosch type. 309 

Mazda type. 309 

tungsten and other filaments. . . 309 
Independent controller starting¬ 
lighting system. 279 

Induction . 27 

Induction principles in generators 

and motors. 27 

capacity of condensers. 29 

circuits. 33 

comparison of generator cur¬ 
rent to water flow. 29 

current and volume. 31 

electric-motor principles. 47 

friction and resistance. 31 

generator principles. 34 

induction . 27 

power comparison. 32 

pressure and voltage. 30 

self-induction . 28 

Inductor-type magneto . 109 

Installing battery on Ford cars. . 569 
Installing unit. Gray & Davis. . . . 562 

Bendix drive. 564 

chain drive. 563 

final assembly. 564 

generator-motor . 562 

Instruments and protective devices 362 
Irregular sparking, effect of. 129 

J 

.1 effe ry - B i j u r sta r ti n g-1 i gh t i n g 

system. 325 

Joint hydrometer and voltmeter 

tests.650, 687 

I. 

Lamp voltages. 310 

Laws of magnetic attraction and 

repulsion. 21 

Lead burning . 661 

first method of burning. 662 

hydrogen gas outfit. 665 

illuminating gas outfit. 663 

second method of burning. 662 

type of outfit. 661 

use of forms to cover joint. . .. 663 
Leece-Neville starting-lighting sys¬ 
tem .. 443 


PAGE 


Lighting. 309 

dimming devices. 312 

headlight glare. 312 

incandescent lamps. 309 

lamp voltages . 310 

lighting batteries. 310 

reflectors . 311 

Lighting batteries . 310 

Lines of megnetic force. 25 

Low-tension magneto. 103 

Magnetic field. 23 

Magnetic substances . 22 

Magnetism . 2u 

electromagnets . 22 

laws of magnetic attraction and 

repulsion . 21 

lines of magnetic force. 25 

magnetic field. 23 

magnetic substances . 22 

natural and artificial magnets. 20 

poles of magnet. 21 

solenoids . 25 

Magneto mounting. 167 

Magneto speeds . 137 

Magnetos 

compound distributor . 115 

Dixie magneto . 112 

high-tension magneto . 105 

inductor-type magneto. 109 

low-tension magneto. 103 

j'tath of current... 116 

working principle. 102 

Magnets, natural and artificial. . . 20 

Motor failure, causes of. 192 

Motor-generator . 673 

Motor testing, adjustment, and 

maintenance . 192 

causes of motor failure. 192 

solving troubles . 194 

testing . 192 

Motor windings and poles. 291 

commercial forms. 292 

standard designs. 291 

N 

Non conductors. 10 

North East battery. 579 

mounting battery. 583 

mounting starter. . .. 580 

operating instructions. 584 

preparing engine . 579 

North East starting-lighting sys¬ 
tem . 452 

O 

Ohm’s law. 5 

Operating devices. Disco. 411 

























































































INDEX 


PAGE 


Overhauling battery. 655 

checking connections. 658 

dismounting cells. 656 

reassembling battery. 657 

reconnecting cells . 660 

renewals. 660 

treating plates . 657 


P 


Poles of magnet. 21 

Power unit. 6 

Pressure and voltage. 30 

Primary batteries. 86 

defects of dry cells. 86 

liquid batteries. 87 

Protective devices. 373 

Delco. 373 

Xorth East . 452 


Protective devices and instruments 

284, 325, 471, 495 


R 


Redectors. 311 

Remy ignition system. 178 

detecting grounds . 179 

ignition switch . 180 

interrupter and distributor. . . . 180 
Remy starting-lighting system. . . 467 

Remy single-unit type. 472 

six-volt; two-unit; single-wire 

type. 467 

Resistance. 5 


S 


Seating brushes . 

Self-induction. 

Shaft-driven Genemotor . 

adjustment of gears. 

ammeter. 

failure to start. 

mounting Genemotor. 

operating. 

preliminary adjustments. 

Short-circuits and grounds. 

Simms-Huff starting-lighting sys¬ 
tem . 

Solenoids . 

Solving motor troubles. 

breakdown of magneto. 

care of Ford magneto. 

inspection of contact-breaker. . 

leakage at distributor. 

magnet recharger. 

remagnetizing. 

spark plugs. 

sparking at safety gap. 

Sources of current. 

chemical sources of current.... 


398 

28 

537 

540 

546 

546 

540 

545 

537 

15 


479 

25 

194 

196 
200 

194 

195 
198 

197 

195 

196 
86 
86 


759 

PAGE 


Sources of current (continued) 
induction sources of ignition 

current magnetos. 102 

voltage and spark-control de¬ 
vices . 8b 

Spark advance and retard. 129 

adjusting for time factor of 

coil . 130 

analysis of oscillograph dia¬ 
grams . 134 

calculation of small time allow¬ 
ance .'. 130 

magneto timing . 132 

Mea method of advancing spark 135 
Spark plugs 

electrode arrangement. 96 

fundamental requisite. 95 

magnetic plugs. 97 

plug threads . 98 

priming plugs . 98 

series plugs . 97 

waterproof plugs . 98 

Spark timing . 125 

advance and retard. 129 

automatically timed systems... 138 
effect of irregular si)arking. . . . 129 

firing order . 143 

ignition setting point. 141 

ignition-system fixed timing 

point. 138 

magneto speeds. 137 

Specific gravity . 627 

Splitdorf instructions . 492 

failure of engine to start. 492 

oiling of starting motor. 492 

regulation. 489 

Splitdorf starting-lighting system 

.487, 586 

mounting starter . 587 

preparing engine. 586 

six-volt; two-unit . 488 

twelve-six-volt; single-unit .... 487 

wiring . 588 

Standardization of voltage. 282 

variation by manufacturers . . . 287 

voltage standards. 286 

Standard types of ignition sys¬ 
tems . llf^ 

double-spark ignition . 124 

dual ignition system. 118 

duplex ignition system. 123 

Ford magneto. 124 

Starting and lighting develop¬ 
ments, effect on ignition. 169 

Starting and lighting storage bat¬ 
teries . 623 

care of battery. 632 

importance of battery in start¬ 
ing and lighting. 623 





























































































760 


INDEX 


PAGE 


Starting and lighting storage bat¬ 
teries (continued) 
storage battery requires careful 

attention . 623 

principles and construction.... 624 
Starting and lighting systems, 

analysis of types. 315 

Auto-Lite system. 334 

Bijur system. 343 

Bosch-Eushmore system. 360 

Delco system. 367 

Disco system. 411 

explanation of wiring diagrams 315 

Gray & Davis system. 416 

Heinze-Springfield system. 435 

Leece-Neville system . 444 

North East system. 452 

Remy system. 467 

Simms-Huff system. 479 

Splitdorf system. 487 

use of protective and testing de¬ 
vices . ■.. 325 

U.S.L. system. 493 

Wagner system. 507 

Westinghouse system. 521 

Starting motor 

Auto-Lite . 336 

Bijur. 345 

Boseh-Rushmore . 360 

Delco. 384 

Dyneto . 414 

electromagnetic switch . 529 

Gray & Davis. 417 

Heinze-Springfield . 436 

magnetic engaging type. 528 

motor windings and poles. 291 

Remy . 471 

requirements in design. 289 

voltage. 291 

wide variation in starting speed 290 

Starting speeds. 290 

Starting switch . 385 

Storage battery, principles and 

construction. 624 

action of cell on charge. 627 

action of cell on discharge. 628 

capacity of battery. 629 

construction details. 631 

Edison cell not available...... 632 

function of storage battery. . . . 624 

parts of a cell. 625 

specific gravity. 627 

Storage cells. 87 

Sulphating . 644 

Switch tests. North East. 463 

ground test. 463 

mechanical and electrical char¬ 
acteristics . . . .'. 466 

operation test. 463 

replacing Dodge chain. 463 


PAGE 


Switch and wiring. Ford car. 565 

battery cables. 568 

charging wire and starting 

cable. 568 

coil and magneto wiring. 568 

wiring for lights. 568 

Switches in starting and lighting 

systems. 301 

electrically operated switches. . 304 
miscellaneous starting switches. 303 
Westinghouse starting switch. . 302 
Symbols for wiring diagrams. ... 315 


T 

Tail and side lights, horn, etc. . . . 570 


Tension. 81 

Testing Heinze-Springfield system 572 

Testing armatures. 401 

Testing circuit-breaker. 397 

Testing cut-out . 394 

Testing field coils. 406 

■ grounded fields. 407 

open-circuits in fields. 406 

short-circuits between coils.... 410 
short-circuit between windings. 407 

voltmeter field tests. 408 

Testing Gray & Davis generator. . 559 
Testing rate of battery charge. . . 681 

Testing wiring system. 193 

Tests of wiring. 390 

locating breaks in wires. 394 

locating grounds . 391 

locating shorts . 391 

Third-brush adjustment, Delco. . . 389 
Tracing for grounds in wiring. . . 326 
Transmission and regulation de¬ 
vices . 293 

automatic engagement. 297 

back-kick releases . 300 

clutches . 298 

driving connection. 296 

electric horns . 307 

fuses. 305 

installation . 293 

switches . 301 

Two-wire system diagram. 322 

Chevrolet-Auto-Lite type .322 

Jetfery-Bijur type. 325 

Typical firing orders. 143 

U 

U.S.L. instructions. 496 

ammeter . 503 

battery cut-out. 503 

brush pressures. 500 

external regulator . 501 

radial and angular brushes. . . . 501 

starting switch. 500 

testing carbon pile. 503 

touring switch. 496 

























































































INDEX 


PAGE 

U.S.L. starting-lighting system. . . 

493, 505 

U.S.Nelson starting-lighting sys¬ 


tem .. 507 

Unisparker, operation of. 173 

Units and wiring plans. 270 

V 

Voltage. 291 

Voltage drop. 9 

Voltage spark control devices. ... 88 

changes in ignition methods. . . 88 

coils and vibrators. 90 

condenser. 94 

contact makers. 89 

distributor .. 93 

spark plugs. 94 

Voltage standards . 286 

Voltage test.650, 687 


W 

Wagner instructions.511, 517 

Wagner starting-lighting system. 507 
Westinghouse-Ford operating in¬ 
structions . 608 

Westinghouse-Ford starter instal¬ 
lation . 594 

Westinghouse generators . 523 

Westinghouse ignition unit.. .171, 606 


761 


PAGE 

Westinghouse instructions . 521 

battery charging . 521 

lire prevention . 522 

weak current. 522 • 

Westinghouse starting-lighting sys¬ 
tem . 521 

Wiring . 162 

calculating size cable. 165 

effect on lights. 165 


importance of good connections 166 
importance of voltage drop. . . . 164 
necessity for high-tension cables 162 


Wiring diagrams 

Apperson . 348 

Auto-Lite . 339 

Rosch-Kushmore . 364 

Buick . 378 

Cadillac . 375 

Delco .375, 385 

Dyneto . 414 

Gray & Davis. 421 

Heinze-Springlield . 438 

Hupp . 348 

Jeffery . 345 

Leece-Neville . 445 

North East . 454 

Scripps-Booth . 348 

Splitdorf .487, 588 

U.S.L. 496 

Wagner . 507 

W^estinghouse.521, 526 

Winton . 345 

Wiring diagram symbols. 315 















































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